- For the filling
- 100g plain flour, plus 1 extra tablespoon
- 1/2tsp baking powder
- 300g rhubarb, cut into 1cm slices
- 2tbsp light soft brown sugar
- 125g unsalted butter, softened
- 100g caster sugar
- 2 large free range eggs
- 1tsp vanilla extract
- For the topping
- 75g unsalted butter, softened
- 75g plain flour
- 125g soft brown sugar
- 50g walnuts or hazelnuts, roughly chopped
- 50g large rolled oats
1 Preheat the oven to 200°C / fan 180°C / gas mark 6. Line a rectangular shallow baking tin (we used 20cmx30cm) with baking parchment.
2 For the crumble topping place the butter, flour and sugar in a bowl then using a fork mash it all together until you have large, coarse crumbs. Mix in the walnuts or hazelnuts and oats. Set aside in the fridge to chill.
3 To prepare the rhubarb, place it into a bowl with the tablespoon of plain flour and the soft brown sugar then toss together well.
4 For the base, place the flour in a bowl and mix in the baking powder and a pinch of salt.
5 Place the softened butter in a bowl, add the sugar and mix together with a whisk until light and fluffy. Add the eggs one at a time followed by the vanilla. Fold in the flour mixture, spoon into the prepared tin and bake for 15 minutes.
6 Remove from the oven, cover with half the crumble mixture then the rhubarb and finally the remaining crumble on top. Bake for a further 45 minutes until firm to the touch with a soft cooked sponge base and a really crunchy crumble topping.