Preheat the oven to 160ºC . Cut out three 25 cm parchment paper circles and one 25 cm cardboard circle. Set the parchment circles on baking sheets. Beat egg whites to soft peaks and gradually add 2.5 tablespoons of sugar and continue beating until stiff. Combine 2.5 cups of powdered sugar and ground almonds; fold into egg whites. This mixture can now be used to form layers, or designs or whatever your choose. Simply spoon mixture into a pastry bag fitted with the tip of your choice, and pipe your designs onto parchment paper covered baking sheets. Dust lightly with powdered sugar (optional.) Then bake the your meringue until crisp and very lightly golden (for designs about a 1 cm thick, it takes 25 to 30 minutes.) Cool on the finished baked meringue on racks.