A classic German dessert item using a variety of red berries. Serve with vanilla ice cream, vanilla pudding, rice pudding, whipped cream, etc. You can use fresh or frozen unsweetened raspberries, strawberries, red currants, or a combination of the three.
Combine berries and sugar in non-stick saucepan over medium heat; bring to a boil while stirring constantly.
Whisk cornstarch into cold water in a small bowl until dissolved completely; stir into the berry mixture. Reduce heat to medium low and cook mixture at a simmer until it begins to thicken, about 3 minutes.
Remove berry mixture from heat. Stir lemon juice and vanilla extract into the berry mixture; transfer to a bowl. Cover bowl with plastic wrap and refrigerate for 24 hours.