These pies are the quintessential textural crunch/squidge/crunch sandwich that I am totally smitten with. I adore the feeling of cradling one of these pies, still warm, the moment before eating. The words below are beyond a recipe and into blueprint territory because you can make these with so many different fruits and spike the crumble with spices or nuts. Keep the custard a classic vanilla though, a safe and creamy canvas on which to create your fruit crumble masterpiece.
Makes 8 irresistible individual pies
Takes If all the components are ready, 30 minutes – or 3 hours if starting from making the dough. Make the other components while the dough rests.
WHAT YOU NEED
Butter Oat Streusel
100 g (3½ oz) old-fashioned or rolled (porridge) oats
120 g (4½ oz) plain (all-purpose) flour
100 g (3½ oz) light muscovado (or soft brown) sugar
150 g (5½ oz) unsalted butter, very soft and squidgy
2 g (1/16 oz/¼ teaspoon) fine sea salt
3 g (⅟₁₀ oz/1½ teaspoons) freshly ground cinnamon
Roasted Rhubarb with Ginger
2 small bunches rhubarb, about 400 g (14 oz) in total
5 cm (2 in) piece of ginger
juice of 1 orange (or other mid-acidic citrus, such as mandarin or tangelo)
40 g (1½ oz) caster (superfine)
2 tsp ground cinnamon
Super Flaky Pie Crust
240 g (8½ oz) plain
2 g (1/16 oz/¼ teaspoon) fine sea salt
190 g (6½ oz) unsalted butter,
cold and diced
40 g/ml (1½ oz) iced water
20 g (¾ oz) egg yolk
(from approx. 1 egg)
Vanilla Pastry Custard
250 g/ml (9 oz) full-fat (whole) milk
1 vanilla bean
60 g (2 oz) egg yolk (from approx. 3 eggs)
15 g (½ oz) plain (all-purpose) flour 10 g (¼ oz) cornflour(cornstarch)
65 g (2¼ oz) caster (superfine) sugar
25 g (1 oz) unsalted butter, room temperature
WHAT TO DO
Super flaky pie crust
Makes 500 g (1 lb 2 oz): enough for one 25 cm (10 in) pie dish or eight 8 cm (3¼ in) × 10 cm (4 in) individual pie tins.
Takes About 20 minutes to make and roll. At least 2 hours to rest in the freezer, but best frozen overnight. Up to 50 minutes to blind bake.
Keeps Frozen and unbaked for 3 months in the freezer. After being baked, airtight and room temperature for about 4 days.
Biting into this crust is all about the joyful sensation of collapsing shards of flakiness. It is downright Herculean
in Rhubarb custard crumble pies with the filling it supports, and can be used for savoury applications too: quiches, sausage rolls or pot-pie tops.
The dough gets a little of its strength from the gluten in the flour, so make sure you use a regular plain (all-purpose) flour with a 10% gluten level. And when you roll it out, you will find there will be marbled smears of butter here and there. This is not just a good thing, it’s actually perfect. I hope this recipe becomes your dough-to.
Put the flour and salt in a wide mixing bowl. Using your fingertips, rub the butter into the dry ingredients just until the butter lumps are the size of whole almonds and the flour has just taken on a yellowy hue. When tossing through your fingers, it should feel like silky ground almonds with buttery lumps throughout.
These large butter lumps are going to melt during baking, creating steam, which will flake the pastry apart tremendously.
Combine the iced water and egg yolk and add to the buttery flour. Keep mixing with your hands, lightly squeezing the dough together, until it looks like shaggy playdough. Loosely wrap the dough in plastic wrap, then press the dough into a 2 cm (¾ in) thick disc, gently squeezing around the edge to smooth out any cracks. If the dough is not too warm, you can start rolling now. Or if it feels sticky, chill in the fridge for at least 15 minutes – just ensure that the dough is cool and pliable before rolling.
Place the dough on a lightly floured surface and press it out a little with the palm of your hand to ease it into the start of rolling. This helps to prevent large cracks. Give the dough one or two short, pressured rolls with the pin before lifting and moving the dough 90 degrees, making the rolls longer as the dough circle widens. Dust underneath the dough at regular intervals to prevent sticking.
For a 25 cm (10 in) pie tin, roll out the dough to a 31 cm (12¼ in) circle, about 5 mm (¼ in) thick. Trim, then gently lift and flop the dough into the tin.
Working in sections, tuck the dough right into the edge and against the side of the pie tin to prevent air pockets. With scissors, snip the excess dough off the edge, leaving a 5 mm (¼ in) overhang. Tuck this under all the way around, then crimp the edge. Freeze for at least 2 hours or preferably overnight before blind baking.
For individual tins, roll the dough into strips at least as wide as your pastry cutter, then cut out circles. Line snugly into the tins. Use your fingers to push off any overhang.
To blind bake, preheat the oven to 180°C (350°F). Cover the frozen dough with a piece of aluminium foil, tucking it snugly into the edge of the tin. Fill the lined tin with sugar and bake for 40–50 minutes until the crust is an even biscuity brown colour. Bake the individual tins for 30–40 minutes.
Roasted rhubarb with ginger
Makes About 450 g (1 lb), including juice.
Takes About 30 minutes.
Keeps For 2 weeks refrigerated, then up to 3 months frozen.
Rhubarb is the sour, dynamic soulmate to cheesecake, creamy custards and buttery pastry. Oven roasting rhubarb retains the attractive stalk shape and it’s less likely to explode to a pulpy mush. If it does do this (and the line is chancy between tender and pulpy), it will still be great.
Rhubarb bunches and girths aren’t a standardised affair, so if your bunch is a little small, adjust the other ingredients up or down. I’ve given a bunch weight to help when purchasing. Colour can vary too – seek the thinner bright pink to red stalks. Green-hued rhubarb is still terrific, just lacking the va-va-voom appearance of its crimson cousins.
Preheat the oven to 160°C (320°F). Prepare the rhubarb. Remove the rhubarb leaves (the leaves are poisonous, so trim them off completely and discard), then cut the stems on a diagonal into 6 cm (2½ in) batons. Slice in halve lengthways if the pieces are very thick. Rinse in a colander. Peel and slice the ginger into four coin-like discs.
Have ready a generously sized non-reactive roasting tin (see page 27) that will hold the rhubarb in a single layer, with room around the pieces.
Put the rhubarb batons, ginger, juice and sugar in the tin. Massage all the ingredients together with the knowledge that rhubarb does release a lot of juice when it bakes, so don’t worry about the scarcity of liquid now.
The amount of sugar in this recipe is my ‘sour spot’ but feel free to adjust to your palate. If you over-sugar, correct with a squeeze of lemon at the end. If you under-sugar, add some while the rhubarb is still hot. The sugar will melt and further sweeten the rhubarb. Keep balance in mind – rhubarb’s shot of sour is welcome in sweet baking.
Place a sheet of baking paper over the rhubarb and then cover tightly with foil. Roast for 10–30 minutes* – the timing depending on the thickness of the stalks and the heaviness of your baking vessel. Do the first check at the 10-minute mark. To do this, carefully remove the foil and lift the paper. Steam can burn mercilessly, so allow the first rush of steam to subside. Push a piece of the rhubarb near the centre; it should yield to the lightest poke but still be holding its shape.
If the rhubarb feels like it needs only a smidge longer to soften it, re-foil the tray and rest at room temperature to finish cooking. The residual heat in the roasting tin should cook it to perfect softness. If it needs a little longer in the oven, check it every 5 minutes. When the rhubarb is close to cooked, it can overcook easily.
Remove from the oven and leave to cool with the paper on top. Pack the rhubarb into containers for later delicious uses and store in the fridge. Leave the ginger in with the rhubarb, to impart more flavour in storage. Just remember to remove the pieces before using – it is quite a shock to eat a disc of ginger.
* If you have cooked the rhubarb a little too far, you can attempt to cease the cooking by removing the foil and paper from the tin and putting it in the fridge immediately. Hopefully the lovely rhubarb shape can be saved! If it is officially mush, it will still be great in the Rhubarb custard crumble pies use it for a glaze for the Potato brioche doughnuts.
Vanilla pastry custard
Makes 400 g (14 oz) custard.
Takes About 30 minutes, plus chilling time.
Keeps For 4 days chilled. Don’t freeze.
The word ‘custard’ is a pretty broad term, describing everything from a pourable crème anglaise to this thicker, pudding-esque crème pâtissière. This pastry custard is a strong and adaptable ‘cream’ to add to your baking repertoire: it enriches whipped cream (Beesting buns), can be used as a filling (Doughnuts) or a helpful go-between with pastry and fruit (Rhubarb crumble pies). Two types of flour are employed and, while both do pretty much the same task of permitting the egg yolk to thicken past its natural coagulation temperature, I like using cornflour (cornstarch) for its extra thickening power and flour for its smoother mouthfeel.
Pour nearly all of the milk into a small saucepan, but hold back 1 tablespoon to add to the yolk mix in a minute. Split and scrape the vanilla bean into the milk, then place the pan on the stovetop and scald the milk over a medium–high heat.
‘Scalding’ milk means heating it just to boiling point. You are looking for more than half the surface of the milk to be eagerly bubbling.
Just before the eager bubbling, whisk together the egg yolks, flours, sugar and reserved milk in a small heatproof bowl. The milk helps to bind the egg and flour mix, as it needs a little extra moisture. Don’t do this too far in advance or the mix will form small, hard yolky lumps.
These lumps occur when the sugar starts to draw the moisture out of the yolks – it is referred to as ‘burning’ but that’s a tad dramatic. If it happens, the lumps can be strained out but you’ll lose a little of the yolky setting power, so it is always best to mix the egg and sugar right before adding the hot milk.
Pour half the hot milk into the egg mix and whisk well, then pour in the remainder. Return the mix to the pan, place over a medium–high heat again, and whisk at a medium tempo until the mix thickens. Take extra care to whisk right into the corner of the pan – where the side meets the base. Speed up the mixing as the custard thickens – it will look lumpy but just whisk hard and it will all come together into a thick paste in 1–2 minutes. As soon as the custard comes to the boil, keep whisking for another 30 seconds.*
The flours in this recipe are your insurance policy and will ensure that the egg won’t overcook, so don’t be worried about boiling this – you actually need to boil it for 30 seconds or so, to cook the flour out. Only custards without flour need gentle heat.
Remove the pan from the heat and whisk in the butter. Remove the vanilla bean, scrape the custard into a plastic container and press a piece of plastic wrap on the surface of the custard to prevent a rubbery skin forming. Chill for an hour.**
Butter oat streusel
Makes 450 g (1 lb).
Takes Under 10 minutes to mix.
Keeps For 2 days at cool room temperature. Refrigerated for up to 2 weeks, but recommend baking it from room temperature.
These nubbly, buttery biscuity boulders are fated to be strewn on top of fruit. Bake it from raw on the Rhubarb custard pies, or cook to golden and then crumble over a cheesecake topped with soft fruit, or on freshly glazed dulce de leche doughnuts. I love to use ground oats, as it adds an earthy tone and fragile crispness.
Whiz the oats in a food processor until super fine. Tip into a bowl and add the remaining ingredients. Rub and squeeze the butter in with your fingers until all the dry ingredients are coated in butter and the mix easily forms small buttery clumps when squeezed in your fist.*
Take care not to overmix everything so much that you make an actual dough.
* The most common mistake I see with crumble is that the butter has been under incorporated and it is buttery lumps sitting in dry flour, kind of like the start of a pastry. Easy fix – rub it in a little further. If you have gone too far and into a dough/paste territory, it’s a little harder to fix, as adding more flour will disrupt the ratio of the other ingredients. You can tear pieces off and dot them over the fruit for baking. It will still be delicious, just a bit clumpier.
Preheat the oven to 180°C (350°F). Place the blind-baked crusts, still in the tins, on a heavy baking tray.
Drain the Roasted rhubarb for a few minutes in a colander to remove the excess liquid. Spoon or pipe the Vanilla pastry custard evenly among the crusts, then make a ‘nest’ in the custard by pushing it with the back of a spoon. Strew pinches of the drained rhubarb over the top of the custard.
The pies can be built while the rhubarb and custard are at any temperature – just after cooking, warm or chilled.
Pile the Butter oat streusel on top, allowing a little fruit to be visible around the edge. The fruit will bubble and peek up during baking.
Instead of doing this while the tarts are on the tray, hold the custard-and-fruit-filled pastry crusts over the bowl of streusel and lightly pile it on. That way, any excess crumble will fall back into the bowl and won’t be wasted.
Bake for 20–30 minutes until the fruit starts to bubble at the sides and the crumble is toasty brown on top.* The perfect eating temperature is after a 20-minute cool down.
Keeps Best eaten while warm. Can be wrapped and chilled overnight and refreshed in a low oven the next day.