Although it is traditional to decorate the top of a Simnel cake with 12 marzipan balls to represent the disciples, it is easier to simply rough up the marzipan with a fork. Bake the cake at least three days before serving.
- If possible, prepare the marzipan filling and topping the day before baking, and macerate the dried fruit. To make the filling, use your hands to knead all the ingredients (save the egg whites for the Marzipan Topping and add the egg yolk), adding a spoonful of water if the mixture is too dry to form a moist ball.Cover in plastic wrap and put in a cool place.
- Prepare the Marzipan Topping in the same way, except with the egg whites. Mix the fruit, lemon zest and juice and rum in a bowl and cover.
- When you are ready to bake the cake, preheat the oven to 160C. Line a deep, round 23cm loose-bottomed tin with 2 layers of baking paper. Place the marzipan filling between 2 squares of baking paper and roll out to the same size as the cake tin. Repeat with the marzipan topping. Set both circles of marzipan aside to use later.
- Cream the butter and sugar until very creamy and pale, then beat in the eggs one at a time. Sift the flour and baking powder together and beat in. Add the prepared fruit (including the grated zest of 1 large lemon) and beat in until evenly mixed. Spread half the mixture in the cake tin.
- Lay the filling over the top and cover with the remaining cake mix. Bake for about 1.75 to 2 hours or until the cake is slightly springy in the middle when pressed. Remove the cake from the oven and lay the marzipan topping over it. Rough up the surface with a fork.
- Turn on the grill and place the cake in the middle of the oven. Grill until the marzipan is nicely speckled with golden brown. Remove from the oven and cool before removing from the tin.