1. Combine all praline ingredients to form dry crumbs.
2. For mousse, put berries, water, and sugar into a small pot, bring to a boil. Whisk together cornstarch and water. As the fruit mixture comes to a boil, add the cornstarch mixture. Mix until thick, then turn off the flame.
3. To make patisserie cream, in a bowl, mix sugar, yolks, cornstarch, and vanilla. Heat milk in a small pot, over medium-high flame. When the milk just comes to a boil, add sugar mixture. Continue cooking until mixture is thick and creamy, stirring constantly. Remove pot from flame. Transfer cream to refrigerator. If you prefer an airier cream, beat half a container of whipping cream or nondairy topping and fold into the cooled cream.
4. To assemble, spoon alternating layers of crumb, fruit, and cream into serving glasses.
