- 1 1/2 tablespoons Cognac (optional)
- 1 cup seedless grapes, halved
- 3/4 cup whole blanched almonds
- 1/2 cup sugar
- 1/2 cup unsalted butter, softened
- 3/4 teaspoon vanilla
- 2 large eggs
- 1/3 cup all-purpose flour
- 1/8 teaspoon salt
- Put oven rack in upper third of oven and preheat oven to 400 degrees F.
- If using Cognac, toss grapes with it in a small bowl.
- Pulse half of almonds with 1 tablespoon sugar in a blender until finely ground. Transfer to a small bowl and repeat with remaining almonds and 1 more tablespoon sugar.
- Beat together butter and remaining 6 tablespoons sugar in a bowl with an electric mixer at high speed until pale and fluffy, then beat in vanilla. Add eggs 1 at a time, beating well after each addition. Reduce speed to low and beat in ground almonds, flour, and salt until just combined.
- Divide batter among gratin dishes and press grapes lightly into batter (discard Cognac). Bake in dishes on a baking sheet until cake is firm and pale golden with slightly darker edges, about 20 minutes.
- Transfer cakes to a rack and cool slightly in dishes before serving.