Apple and cinnamon crumble cake

Method

1. Heat the oven to 180°C/160°C fan/gas 4. Toss the bramley apples with the lemon juice in a medium mixing bowl. In a larger mixing bowl, use an electric mixer to cream together the 225g butter, caster sugar and lemon zest until pale and fluffy. Beat in the eggs one at a time, adding 
a little flour with each.
2. Using a large metal spoon, gently fold in the remaining flour and the cinnamon, baking powder and ground almonds. Drain the apple pieces well, pat dry with kitchen paper, then stir into the cake batter (discard any juice left in the bowl).
   Spoon the batter into the tin, gently level, then bake for 45 minutes.
3. As soon as the cake goes in the oven, make the topping. Melt the butter in a frying pan, then add the sliced apples and cook for 2-3 minutes, turning, to caramelise. Leave to cool. In a bowl, rub the butter and flour between your fingertips to a coarse breadcrumb-like mixture. Stir in the sugar, cinnamon and a pinch of salt, then toss with the cooled apple.
4. After the cake has had its 45 minutes in the oven, take it out, then sprinkle the crumble over the top and bake for 15-20 minutes. The cake is ready when the crumble topping is evenly golden brown and the cake feels firm to the touch.
5. Cool in the tin for 10 minutes, then remove from the tin and put on 
a serving plate. Serve warm or leave to cool (see make ahead).