- Nonstick vegetable oil spray
- 3 1/4 cups red seedless grapes, divided
- 2 tablespoons frozen grape juice concentrate (with Concord grapes), thawed
- 1 cup sugar, divided
- 2 teaspoons cornstarch
- 1 1/2 teaspoons raspberry vinegar
- 1 1/2 8-ounce packages cream cheese, room temperature
- 1 1/2 tablespoons all purpose flour
- 1 8-ounce container mascarpone cheese
- 3 large eggs
- Preheat oven to 350°F. Spray 9-inch-diameter cake pan with 2-inch-high sides with nonstick spray. Puree 1 cup grapes and grape juice concentrate in blender until as smooth as possible. Pour puree into medium saucepan. Add 1/4 cup sugar and cornstarch; stir to dissolve cornstarch. Add remaining 2 1/4 cups grapes. Stir over medium heat until mixture thickens, boils, and becomes clear, 2 to 3 minutes (grapes will remain whole); mix in vinegar. Pour into prepared cake pan. Spread grapes in single layer; cool.
- Beat cream cheese, flour, and 3/4 cup sugar in large bowl until smooth. Beat in mascarpone, then eggs, 1 at a time. Spoon batter over grape mixture.
- Bake cake until just set in center, about 45 minutes. Place cake directly into refrigerator; chill uncovered until cold, at least 4 hours and up to 1 day.
- Cut around cake. Place plate over pan; hold plate and pan together and invert. Lift off pan. Cut cake into wedges.
- An Italian cream cheese; sold at many supermarkets and at Italian markets.