Preheat the oven to 180oC. Grease and line a small, deep round cake tin.
Beat together the butter and sugar until light and creamy.
Beat the eggs lightly in a separate bowl then mix in a bit at a time with the butter and sugar. Add a pinch of flour to prevent the mixture curdling.
Fold in the rest of the flour, the ground almonds and the baking powder.
Finely grate in the zest of all three clementines; squeeze in the juice of one.
Lightly stir into the mixture.
Transfer to the tin and bake for about 45 minutes, or until a cake skewer comes out clean.
Meanwhile, make the glaze by squeezing the juice of the remaining clementines into a bowl and stir in the caster sugar.
When the cake is done, leave to cool slightly in the tin, then turn out onto a wire rack. Prick all over with a fork and while still warm, drizzle over the glaze.
When cool, heat the marmalade briefly and spread over the top of the cake.
Decorate with the candied orange peel, glace cherries, and jellies, or any combination of glace fruits.
Serve with a little cream or Greek yogurt.