Food & Cooking Recipes Healthy Recipes Gluten-Free Recipes Plum Jam Be the first to rate & review! By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on July 10, 2019 Print Rate It Share Share Tweet Pin Email Photo: Christopher Testani Prep Time: 20 mins Total Time: 45 mins Yield: 5 cups The skins from stone fruit will contribute color and flavor to the jam. But for a smoother mixture, you can lift the skins out of the cooked jam with a fork. Ingredients 3 pounds plums, pitted 1 ½ pounds sugar (3 ⅓ cups) Coarse salt 2 tablespoons fresh lemon juice Directions Stir together plums, sugar, and 1/4 teaspoon salt in a large heavy-bottomed pot. Bring to a boil, stirring until sugar is dissolved and mashing plums with a potato masher. Add lemon juice; continue to boil, stirring frequently, until bubbles slow, chunks of fruit show at top, and mixture clings to a spoon but falls off in clumps, 10 to 12 minutes. Skim foam from top. Ladle jam into clean containers, leaving 3/4 inch of headroom. Let cool completely. Cover, label, and refrigerate up to 1 month, or freeze up to 1 year. Rate it Print