Cut the vanilla pod lengthways. Scrape out the pulp and add the pod to the milk. Heat milk, do not boil, but keep it hot.
Mix the egg yolks with 3/4 of the sugar in a saucepan and beat until frothy. Mix the flour and cornstarch and stir in vigorously.
Pour in the hot milk, stirring constantly. Put the saucepan on the stove and bring the cream to the boil while stirring until it thickens. Take out the vanilla pod. Whip the cream with the rest of the sugar until stiff and fold into the vanilla cream.