Blackberry and almond crumble cake

    The crumble element in this cake is quite easy to make, as you bake it separately so that you can sprinkle it on at the end. This keeps it crunchy, as you only need to add it shortly before serving.
    We use sunflower oil instead of butter for the sponge, as it gives a wonderful moist fluffiness and means the toasted almond and blackberry flavours are the focus, rather than heavier, richer butter.

    SERVES 10–12
    For the cake
    unsalted butter, for the tin
    125g ground almonds
    5 eggs
    250g sunflower oil
    250g golden caster sugar, plus
    25g for the purée
    125g self-raising flour
    1 tsp baking powder
    1 tsp almond extract
    pinch of sea salt
    350g blackberries
    For the crumble
    50g cold unsalted butter, chopped
    75g plain flour
    25g demerara sugar
    ½ tsp ground cinnamon
    pinch of sea salt
    To decorate
    50g flaked almonds
    icing sugar, to dust (optional)
    Preheat the oven to 155°C/fan 135°C/gas mark 3. Butter a 23cm springform cake tin and line the base with baking parchment.
    Spread the ground and flaked almonds on separate baking trays and toast for 15–20 minutes, turning them with a spatula every 5 minutes so they cook evenly, or until golden brown. Set aside to cool.
    For the cake, combine the eggs, oil and the 250g of sugar in a large mixing bowl using a whisk (or mix in a food mixer fitted with the beater attachment). Whisk for several minutes, or until it turns very thick and pale (don’t skip this step, or you may find that the batter tends to separate). Then add the flour, ground almonds, baking powder, almond extract and salt.
    Take 75g of the blackberries, cut them in half and fold them into the batter.
    Spoon into the prepared tin and bake for 55–60 minutes or until firm to touch and a skewer inserted into the middle of the cakes comes out clean.
    Allow to rest in the tin for 10 minutes, then turn out on to a wire rack to cool.
    Meanwhile, to make the crumble, rub the butter into the flour, sugar, cinnamon and salt in a large mixing bowl to form a texture like crumbs (or you can pulse the ingredients together in a food processor). Spread evenly over a non-stick baking tray and bake for 30–35 minutes or until golden brown, turning with a spatula every 10 minutes to ensure even cooking. Allow to cool.
    To make the purée, place a small pan over a low heat. Tip in 200g of the remaining blackberries with the remaining 25g of caster sugar and 4 tbsp of water and cover the pan. Once the berries have softened (a matter of a few minutes), remove from the heat. Blend to a purée with a hand-held blender, then pass through a fine sieve to remove the seeds. Set aside to cool.
    When you’re ready to assemble the cake, spoon the blackberry purée over the top of the sponge, then scatter the crumble and flaked almonds all over. Finish with the remaining blackberries and dust with icing sugar, if you like. This is lovely served with a dollop of mascarpone.