In a sauce pan, mix together 2,5 glasses of milk, a cup of powder sugar, 1 tbsp flour, 1,5 tbsp corn starch, 5 grams of vanilla and 2 egg yolks until the mixture thickens. When thick, add in the heavy cream and remove from stove for the mixture to cool down. Place your mille-feuilles on an oven tray with greaseproof paper. Place a weight on top of the tray and bake for 25 minutes in 170C heat. Remove from oven, and let your mille-feuilles cool down. Inject the cream mixture you previously prepared in between the mille-feuilles and place another layer of mille-feuille over. Add berries or any type of fruit you wish to. Decorate and serve.