Ingredients
175g unsalted butter, at room temperature, plus extra for greasing 175g dark brown muscovado sugar 3 eggs, lightly beaten 125g self-raising flour 1 tsp baking powder 50g cocoa powder, sifted 175g ground almonds 75g dark chocolate (70% cocoa solids), roughly chopped 400g plums, halved 2 tbsp demerara sugar 3 tbsp plum preserve or jam 2 tbsp toasted flaked almonds
1 Preheat the oven to 180˚C, gas mark 4. Grease and line the base of a 23cm loose-bottomed cake tin. Beat together the butter and muscovado sugar until fluffy, then gradually whisk in the eggs. Fold in the flour, baking powder, cocoa and ground almonds, followed by the chocolate.
2. Spoon the mixture into the prepared tin, levelling the surface with the back of the spoon (it will be quite thick). Arrange the plums on top, cut-side up, pressing them down lightly so that they are pushed slightly into the mixture. Sprinkle over the demerara sugar and bake for 1 hour–1 hour 15 minutes, until a skewer inserted into the centre comes out clean. Cool completely in the tin.
3. Before serving, melt the preserve or jam in a small pan with a splash of water. Brush over the top of the cake and scatter with the flaked almonds.