- 2 lbs rhubarb, trimmed and cut crosswise, 1/2 inch thick (6 1/2 cups)
- 1 lb sugar (2 1/4 cups)
- 1/4 tsp salt
- fresh lemon juice (optional)
- Bring rhubarb, sugar, and 1/4 teaspoon salt to a boil in a large pot, stirring often.
- Cook, stirring often, until bubbles slow, foam subsides, fruit rises to the top, and jam sticks to a wooden or metal spoon when lifted from mixture, about 10 minutes.
- Stir in lemon juice to taste.
- Let cool for 1 hour.
- Refrigerate overnight.