Mix the sultanas and sherry and set aside for 1 hr to soak.
Heat oven to 160C/140C fan/gas 3. Grease a deep, 23cm loose-bottomed cake tin, and line the base and sides with a double layer of baking parchment that comes about 2.5cm above the sides of the tin. In your largest mixing bowl, beat the butter, sugar and vanilla together until pale and fluffy. Beat in the eggs one by one.
Stir in the flour, baking powder, and the ground and flaked almonds. Next, add the soaked sultanas with any remaining sherry, the dried apricots, the mixed peel, and all the zest and juice. Scrape into the cake tin, smoothing out the surface.
Bake on the middle shelf of the oven for 1 hr 25 mins. Poke with a skewer in the centre to check it is cooked – if the skewer comes out with any uncooked mixture stuck to it, bake for 10 mins more before checking again. Cool in the tin. Decorated, or wrapped in greaseproof paper and foil, the cake will keep for up to a month.