1. For the pudding, bring the smaller berries and cherries to a boil in a saucepan until they release their juice. Add more delicate fruits such as strawberries or raspberries last. Stir in the syrup and sugar to taste.
2. Dissolve the cornstarch in a ¼ cup of cold water. Remove the pan from the heat, stir the cornstarch into the fruit mixture and cook briefly over low heat, stirring occasionally. When the pudding turns clear and thickens, remove the pan from the heat immediately. Stir for 2 minutes.
3. Pour the hot pudding into a glass serving bowl. To prevent the glass from cracking when you pour the hot pudding in, put a damp dishtowel underneath the bowl. Refrigerate for several hours until set. Take it out of the refrigerator 30 minutes before serving.
4. For the vanilla sauce, whisk the egg yolks with the sugar and cornstarch. Add the milk and the vanilla. If using a vanilla bean, slit it lengthwise, scrape out the seeds with a sharp knife and add the bean and the seeds to the mixture. Cook over low heat until the sauce thickens, whisking constantly. Refrigerate and stir well before serving.
Source: Nadia Hassani: “Spoonfuls of Germany” (Hippocrene Books, 2004)