Mix 1 egg, 125 g sugar and 1-2 tablespoons of warm water until creamy. Gradually knead in the flour until the dough no longer sticks to the bowl. Grease a springform pan (26 cm Ø). Roll out the dough round (approx. 32 cm Ø) on a floured work surface. Line the form with the dough, press the rim. Prick the base several times with a fork, chill the mould. For the almond paste, beat 4 eggs and 250 g sugar for 6-8 minutes until thick and creamy.
Stir in almonds, lemon peel and cinnamon. Pour the mixture into the mould, smooth it down and cut off any protruding edges of the pastry. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 30-35 minutes until golden brown. Let cool on a cake rack. Remove from the tin and dust with icing sugar. If desired, place a template in the shape of a Jacob's cross on top and dust the cake