Preheat the oven to 240°C/475°F/Gas mark 9. Line a 20cm/8in cake tin with greaseproof paper.
Cream the butter and sugar until light and fluffy, then beat in the eggs, one at a time, along with the ground almonds.
Sift the flour with the salt and baking powder, and gradually add to the creamed mixture along with the fruit and peel. Put the mixture in the prepared cake tin, smooth over and lightly arrange the almonds on top.
Put the cake in the centre of the oven. Immediately reduce the temperature to 170°C/325°F/Gas mark 3, and bake for 1 1⁄2 hours until the cake is firm and springs back at the touch. Allow to cool in the tin.