Rhubarb cinnamon jam is a thick fruit spread made by simmering fresh rhubarb with sugar, lemon juice, and warm cinnamon until it becomes glossy and spoonable.
2 pounds rhubarb, chopped
2 cups granulated sugar
1 tablespoon lemon juice
1 teaspoon ground cinnamon
1/2 cup water
1/2 teaspoon vanilla extract (optional)
Adjust cinnamon for stronger or lighter spice. Add apple for thicker texture. Refrigerate after cooling.