Separate whites from yolks. Beat the egg yolks with sugar until blanching them. Add lemon peel and flour sifted with baking powder and starch. Beat the egg whites of hard snow and add the yolk mixture. Stir gently with a spoon. Cover rectangular baking dish (I use this oven) with baking paper greased with olive oil. Pour the mixture and level the height is the same everywhere. Bake the base of 180C for 10-12 minutes. Remove the paper and let cool completely. Cut the base the size of a rectangular baking dish with high walls (which you will use later). Put to boil the syrup of sugar and water for about 3 minutes. Pull off the fire and add the brandy. Blend peaches with 80 g of powdered sugar, heat without boiling, add pre-soaked gelatine in a little water. Stir to melt well and leave to cool slightly. Beat the yogurt with the remaining powdered sugar and add peach puree. Beat the cream, but not to a solid snow. Let's spend a little more light and fluffy. Throw it in the puree. Stir with a spoon. Cover pan with plastic foil (order then easier to remove if you have a suitable pan with removable walls is convenient) and put the base, syrup and cover with mousse. Leave in the refrigerator for about 3 hours. Remove from pan and cut in four lines. Lines cut into squares, and half of them, so you get triangles type pastries. Garnish with fruit optional.