Pre-heat the oven to 160C(320F) fan-forced.

In an electric mixer, beat the butter and sugar together until they are smooth and creamy.

Keeping the motor running, add the eggs one at a time then gradually add the flour mixing until it's all combined.

Spread the mixture into a greased and lined tin (or foil tin).

Use a serrated knife or a skewer to divide the batter into 20 or 24 squares.

Spoon a blob of raspberry into the middle of each square (to make the raspberry filling, boil the frozen raspberries together until they soften and break up).

Bake the squares for 30-35 minutes.

Leave the baked squares in the tin for 5 minutes then cut them into squares and transfer to a wire rack to cool.

When they have cooled, dust the squares with icing sugar.