WHAT YOU NEED

300 g (10 ½ oz) celeriac
30 g (1 oz/1 ½ tablespoons) olive oil
25 g (1 oz) curly kale
40 g (1 ¾ oz) toasted hazelnuts
75 g (2 ¾ oz) plain (all-purpose) flour
75 g (2 ¾ oz) wholemeal (wholewheat) flour
6 g ( 1/5  oz/1 teaspoon) baking powder
3 g ( 1∕₁₀ oz/1/2 teaspoon) fine salt
50 g (1 ¾ oz/1 medium) egg, at room temperature
150 g (5 ½ oz) milk kefir
100 g (3 ½  oz) unsalted butter, melted
grated zest of 1 lemon

Roast the celeriac ahead of time so it has time to cool. Preheat the oven to 200 C (390 F). Peel the celeriac and roughly chop into 1 cm (½ in) dice. Toss in a roasting tray with 20 g (¾oz/1 tablespoon) of the olive oil, then roast for 25 minutes, or until starting to colour. Set aside to cool completely.

To make the muffins, preheat the oven to 190 C (375 F) and grease six holes of a standard muffin tin with a little butter (you can also use patty pans/cupcake liners if you like).

Trim the kale and cut the hard stems out of the leaves, then roughly chop the leaves. Roughly chop the hazelnuts, reserving some whole for the topping. Combine the celeriac, kale and chopped hazelnuts in a bowl.

Put the flours, baking powder and salt in a medium bowl and whisk to combine, removing any lumps in the flour. In a separate large bowl, whisk together the egg, milk kefir, melted butter, lemon zest and remaining 10 g (1/3 oz/2 teaspoons) olive oil. Fold the flour mixture into the milk mixture until well combined. Add the celeriac mixture and stir with a spoon until evenly distributed through the batter.

Divide the mixture between the muffin holes and top each muffin with a few whole hazelnuts. Bake for 15 minutes, then turn the tin and bake for a further 5–10 minutes until starting to colour on top. Leave in the tin for 5 minutes, then turn out on a wire rack to cool.