Rhubarb tart with oatmeal crumble

1 teaspoon baking powder

100g unsalted butter, softened at room temperature and diced

85g caster sugar

1 egg yolk

300g rhubarb- trimmed and roughly chopped

2 tablespoons dark brown soft sugar

50g unsalted butter- softened at room temperature and diced

60g caster sugar

50g rolled porridge oats

1 Preheat the oven to 200˚C/400˚F Gas 6. Sift the flour and baking powder into a mixing bowl. Rub the butter into the flour mixture with your fingertips until it looks like breadcrumbs. Stir in the sugar and egg yolk and mix until a dough forms. Transfer the dough to the greased tart tin and push and press it into the tin until the base and sides are evenly covered with a neat layer of dough.

2 To make the filling, put the rhubarb and brown sugar in a bowl and mix until the rhubarb is evenly coated, then transfer to the pastry case and spread roughly over the base of the tart. In a separate bowl, mix the butter, caster sugar and oats together until you have a rough mixture like a crumble topping. Scatter roughly over the rhubarb filling. Bake in the preheated oven for 30 minutes, or until the crumble topping and pastry are golden brown.