The sweet midwinter: Apple & walnut crumble pie

I cannot overstate how unbelievably good this is – pastry just-as-you-want-it crumbly, filling rich and custard-like and a topping the kind of stuff I could devour on its own by the spoonful. Best served warm with a little cream or a scoop of ice cream.

SERVES 8-10

For the crust

220g cold salted butter, cut into cubes, plus extra for the tin

250g plain flour

180g cream cheese

For the filling

5 small or medium apples, preferably Pink Lady

400ml crème fraîche

200g caster sugar

½ tsp fine sea salt

50g plain flour

1 egg

For the topping

100g walnuts

50g plain flour

110g salted butter, softened

50g caster sugar

50g demerara sugar

1 tsp ground cinnamon

• Butter and line a cake tin (I use a springform that is 24cm in diameter). Combine the crust ingredients in a food processor and pulse until a soft dough forms. Roll it out into a large circle and line the tin, pressing it up the sides. Set in the fridge for 30 minutes or so.
• Meanwhile, preheat the oven to 230C/210C fan/gas 8, then core and finely slice the apples. Combine the crème fraîche, sugar, salt and flour in a mixing bowl. Crack the egg into a smaller bowl, lightly beat with a fork and stir into the mixture. Add the apple slices and stir well. Spoon the filling into the pie crust and bake in the oven for 10 minutes, then reduce the oven temperature to 175C/155C fan/not-quite gas 4 and bake for a further 35 minutes.
• Roughly chop the nuts and toss them into a mixing bowl. Add the rest of the ingredients for the topping and mix well, rubbing in the butter so you have a lumpy crumble. Spoon over the pie and bake for 20 minutes, or until golden brown. Leave to cool in the tin before serving slightly warm.

TIP Bake this up to a day in advance, if you like, then cover with foil and reheat in an oven heated to 150C/130C fan/gas 2 for 25 minutes.