RHUBARB CRUMBLE CAKE
Tart rhubarb is so good in baking, especially when paired with brown sugar and fragrant spices – as it is in this cake. The crumble topping adds another layer of deliciousness here. In theory, this cake will keep for a few days in an airtight container, but it’s highly unlikely it will have to.
Preparation Time 15 minutes | Cooking Time 1 hour | Serves 6–8
400 g (14 oz) rhubarb, trimmed and cut into rough 3–4 cm (1½ inch) pieces
110 g (3¾ oz/½ cup) brown sugar
110 g (3¾ oz/½ cup) caster (superfine) sugar
160 g (5½ oz/2/3 cup) softened butter
1 vanilla bean, split and seeds scraped or 1 teaspoon vanilla extract
Finely grated zest and juice of 1 orange
2 eggs
220 g (7¾ oz) plain (all-purpose) flour
80 g (2¾ oz/¾ cup) hazelnut meal
2 teaspoons ground cinnamon
2 teaspoons ground ginger
1 teaspoon baking powder
¾ teaspoon bicarbonate of soda (baking soda)
160 ml (5¼ fl oz) buttermilk, well-shaken
CRUMBLE TOPPING
50 g (1¾ oz/1/3 cup) plain (all-purpose) flour
50 g (1¾ oz) brown sugar
3 tablespoons butter, cut into little cubes
40 g (1½ oz/¼ cup) toasted hazelnuts, coarsely chopped
Preheat the oven to 170°C (325°F). Butter and line a 15 x 30 cm (6 x 12 inch) rectangular cake tin or a 23 cm (9 inch) round cake tin with baking paper. Toss the rhubarb in a bowl with 1 tablespoon of each of the sugars and set aside.
To make the crumble topping, rub the flour, sugar, butter and a good pinch of sea salt in a bowl until little clumps form, then mix in the hazelnuts. Spread the mixture on a tray, pressing together a little to keep clusters of mixture together, then put in the freezer while you make the cake batter.
Beat the butter, remaining sugars, vanilla and orange zest in an electric mixer for 2–3 minutes until light and fluffy, then beat in the eggs, one at a time, scraping down the sides and base of the bowl and beating to combine before you add the next egg. Add the flour, hazelnut meal, spices, baking powder, bicarbonate of soda and orange juice and mix on a low speed. Beat to combine, gradually adding the buttermilk as you do, until just smooth, then spoon into the cake tin.
Smooth over the top and then scatter over half the crumble mixture. Pile on the rhubarb and drizzle over any juices that have formed in the bottom of the bowl. You may need to pile the rhubarb up a bit – don’t worry if it looks higgledy-piggledy, it will settle as it bakes. Scatter over the rest of the crumble topping and bake for 50 minutes–1 hour until golden brown and firm in the centre. Cool slightly in the tin, then transfer to a wire rack to cool completely, or serve warm.