Knead flour, icing sugar, butter in pieces and 1 egg with your hands to a smooth dough. Wrap the dough in foil and chill for about 30 minutes. Grease a springform pan (24 cm Ø). Roll out the dough on the floured work surface until round (approx. 30 cm Ø) and line the form with it. Press down the rim and put the mould in a cold place
Cut the vanilla pod lengthwise and scrape out the pulp. Boil up the milk, vanilla pod and pulp. Remove from the heat and leave to stand for about 10 minutes. Whisk 3 eggs, sugar and vanilla sugar. Mix starch and cream and stir into the eggs. Remove the vanilla pod from the milk and pour the milk into the egg mixture while stirring constantly
Briefly bring the milk mixture to the boil in a saucepan while stirring constantly. Pour into a bowl and let it cool down lukewarm while stirring occasionally. Pour the cream into the springform pan and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 20 minutes
Increase temperature. Bake in the preheated oven (electric cooker: 225 °C/ convection oven: 200 °C/ gas: see manufacturer) for another 10-15 minutes until the flan is well browned. Leave to cool in the switched-off oven with the door open for about 30 minutes, then let it cool down on a cake rack. Dust the flan with icing sugar before serving
waiting time approx. 1 1/4 hours