Ingredients
1 pound rhubarb, cut into 1/2-inch pieces (about 3 1/2 cups)
6 ounces raspberries (1 1/2 cups)
12 ounces sugar (1 1/2 cups)
2 strips lemon zest (each about 3 inches by 1/2 inch), plus 1 tablespoon fresh juice
1/4 teaspoon kosher salt (we use Diamond Crystal)
Preparation
Bring rhubarb, raspberries, sugar, lemon zest and juice, and salt to a boil in a heavy pot, stirring often. Cook, continuing to stir often, until bubbles slow, foam subsides, fruit rises to the top, and jam sticks to a wooden or metal spoon when lifted from mixture, 8 to 10 minutes.
Let cool completely, about 2 hours. Refrigerate in an airtight container until cold, at least 4 hours and up to 1 month, or freeze up to 3 months.
