Stir 1 cup sugar into the strawberries, and let stand at room temperature. Cook rhubarb with remaining 1 cup sugar in a medium stainless steel saucepan over medium heat 10 minutes or until fruit is softened and sugar is melted, stirring constantly.
Stir strawberry mixture into rhubarb mixture; pulse in a food processor 8 to 12 times or until slightly chunky, stopping to scrape down sides. Transfer to a medium glass or nonmetallic bowl. Let stand 15 minutes. Gradually stir in pectin. Stir 3 minutes; let stand 30 minutes.
Spoon mixture into clean (1⁄2-pt.) jars or other freezer containers, leaving 1⁄2-inch headspace. Seal, label, and freeze upright. Store in freezer up to 1 year. Thaw completely (about 1 day) in refrigerator before using. Refrigerate after thawing, and use within 3 weeks.
We tested with Ball RealFruit Instant Pectin.
Canning and Preserving Special Edition