Pour the shortcrust pastry into a cake tin (classic: with a wavy edge). Cover the bottom and edge of the tin with batter and prick several times with a fork.
Preheat the oven to 180 °
Beat the sugar and eggs until frothy, then stir in the cornstarch. Bring the milk to the boil together with the scraped-out vanilla pod. Pour through a sieve to the sugar-egg-starch mixture and stir everything quickly. The mass becomes quite solid very quickly. Spread the thickened cream on the dough and smooth it out. Bake in the oven for 30-40 minutes. The flan is ready when the top has turned golden brown.
The flan has to cool down properly before it is eaten so that it gets its typical firm consistency.