Beat together the softened butter, sugar, eggs and flour until soft and creamy (approximately 2-3 minutes). Add the vanilla, baking powder, ground almonds and mix along with half the fruit. Toss lightly.
Transfer to lined muffin tins and spoon the mixture two-thirds full. Top the muffins/cakes with the remainder of the fruit dusted with Demerara sugar.
Bake in the oven at 190° Gas No 5 for approximately 25 minutes.
Serve hot or cold dusted with icing sugar on their own, or with a little yoghurt.