Combine rhubarb, raspberries, water and sugar in a medium nonreactive saucepan. Cover and cook over medium heat until rhubarb is very tender, 10 to 15 minutes. Stir in vanilla. Serve warm or cold.Advertisement
Make Ahead Tip: The sauce will keep, covered, in the refrigerator for up to 4 days.
Keep food fresh: If you’re storing food in your fridge for a few hours or more, it’s best to keep it in an airtight container or in a container covered tightly with foil. Foil is best at creating a barrier that doesn’t let unwanted flavors in (or out) while you store your food.