Beat together the butter, sugar, eggs, vanilla and flour in a bowl until pale and creamy. Stir in the ground almonds, milk and half the fruits.
Spoon the mixture into a greased and lined 28 x 24 cm (11 x 9¼ inch) shallow baking tin or roasting tin (see
Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 40–45 minutes or until just firm to the touch and a skewer inserted into the centre comes out clean. Leave to cool in the tin, then transfer to a board and peel off the lining paper. Sprinkle with caster sugar and cut into squares.