Melt the butter. Pour the shortbread biscuits into a freezer bag and crumble finely with a cake roll. Mix cookie crumbs and butter. Spread the bottom of a square springform pan (24 x 24 cm) with oil. Spread the crumble mixture on it and press it down to a smooth base and chill for about 30 minutes.
Pour yoghurt into a bowl, add 3 tablespoons of sugar and cream powder and mix briefly with the whisks of the hand mixer at the lowest setting. Then whisk at highest setting for about 3 minutes. Spread the cream on the crumb base and smooth it down. Chill for at least 1 hour. Wash the fruit, dab dry and clean. Quarter strawberries. Just before serving, place the fruits on the cake. Mix 2 level tablespoons of sugar and cake glaze powder in a saucepan, stir in apple juice. Bring to the boil briefly while stirring. Spread the glaze over the fruits from the middle.
Quarter strawberries. Just before serving, place the fruits on the cake. Mix 2 level tablespoons of sugar and cake glaze powder in a saucepan, stir in apple juice. Bring to the boil briefly while stirring. Spread the glaze over the fruits from the middle. Allow to set. Decorate with mint and dust with icing sugar