It's absolutely worth the time to cook grapes for three hours. Low and slow heat concentrates the grape-y sweetness and turns fruit buttery-soft with almost no effort.
1 1/3 cups seedless black grapes
1 1/3 cups seedless red grapes
1 1/3 cups seedless green grapes
3 tablespoons sugar
2 cups plain fat-free Greek-style yogurt, divided
1/4 cup walnut halves, toasted and coarsely chopped, divided
8 teaspoons honey, divided
Thinly sliced fresh mint (optional)
How to Make It
Preheat the oven to 200°. Coat a jelly-roll pan with cooking spray.
Rinse grapes; drain well, leaving slightly moist. Combine grapes and sugar in a large bowl; toss to coat. Arrange grapes on prepared jelly-roll pan. Bake at 200° for 3 hours or until grapes soften but still hold their shape. Remove from oven; cool completely.
Spoon 1/4 cup yogurt into the bottom of each of 4 parfait glasses. Top each serving with about 1/3 cup grapes, 1 1/2 teaspoons walnuts, and 1 teaspoon honey. Repeat layers with remaining ingredients; garnish with sliced mint, if desired.