Rhubarb & custard slab pie

Bake an American-style lattice pie, presented in a slab for easy portioning. Of course the rhubarb and custard combo is quintessentially British

Prep:35 mins
Cook:45 mins
plus 1 hr chilling

Serves 12
More effort

Nutrition per serving

kcal 606
fat 27g
saturates 15g
carbs 79g
sugars 34g
fibre 3g
protein 9g
salt 0.7g

Ingredients

600g plain flour?
150g icing sugar
300g cold butter, cut into small pieces
3 egg yolks, plus 1 egg, beaten
75g instant custard powder (we used Bird’s)
200g caster sugar, plus 1 tbsp
550ml whole milk
2 tsp vanilla bean paste, extract or 1 vanilla pod, seeds scraped out
700g forced rhubarb, ends trimmed and cut into 2cm pieces
1 tbsp cornflour

Tip

Different flavoured fillings

You could also use lightly stewed dessert apples or pears, or seasonal berries.

How to decorate your pie

Use a pizza cutter to cut eight thin strips of pastry, working from one of the shorter edges. Roll out the remaining pastry so it’s a little longer, then cut into thin strips. Lay the longer strips over the length of the pie, and the shorter strips diagonally going the other way. Trim the edges of the pie and use the off-cuts to cut out enough polka dots (we used the large end of a piping nozzle) to go all the way around the edge.

Method

Put the flour, icing sugar, butter and ½ tsp salt in a food processor, and blend until combined. Add the egg yolks and 2 tsp cold water, then blitz again until the dough starts to form clumps around the blade. Tip onto your work surface and knead briefly to bring the dough together. Remove about a third of the dough, shape both pieces into discs and wrap. Chill for at least 30 mins. Alternatively, mix the flour, sugar and salt in a bowl and work in the butter with your fingertips before adding the yolks and water.
Mix the custard powder and 75g of the sugar with 100ml of the milk to make a smooth paste. Warm the rest of the milk in a saucepan. Pour the warm milk over the custard powder mix, stir and pour back into the pan with the vanilla. Heat until you have a really thick custard. Transfer to a bowl, cover to prevent a skin forming, and chill for at least 30 mins or until cold.
Heat oven to 200C/180C fan/gas 6 and put a baking sheet on the middle shelf. Toss the rhubarb, cornflour and remaining 125g sugar together in a bowl. Roll out the larger of the two pieces of dough on a lightly floured surface, to a rectangle large enough to line the base and sides of a 25 x 35cm shallow baking tin, about ½cm thick. Lift the dough over your rolling pin and drape into the tin, leaving any excess hanging over the edges. Stir the set custard and spread over the pastry base. Top with the rhubarb, in neat lines or randomly, and scatter any sugary bits over the top.
Roll out the smaller piece of pastry until large enough to cover the top of the pie. You can either cover the pie completely, leaving a few holes for the steam to escape, or create a decorative topping. When you’re happy with your design, brush the top with beaten egg and scatter over the 1 tbsp caster sugar. Place the tin on the tray on the middle shelf and bake for 40-45 mins, until the pastry is deep golden brown and the filling is bubbling. This pie is best served at room temperature or just warm, so leave to cool for at least 1½ hrs before slicing.