Grilled Pound Cake with Warm Berry Sauce

From Rachael Ray

2 heaping cups mixed frozen berries, such as raspberries and blueberries (12 ounces)
juice of 1/2 lemon (1 tablespoon)
2 Tbsp granulated sugar
1/4 tsp pure vanilla extract
1 1/2 tsp cornstarch
1 store bought pound cake, sliced 3/4" thick
4 Tbsp unsalted butter, melted

In a small saucepan over medium-low heat, combine the berries, the lemon juice, i tablespoon of the sugar, the vanilla and 1/4 cup of water. Cook, covered, until the berries are softened, about 10 minutes. Stir the sauce, partially mashing the berries. Taste and add more sugar if the mixture is too tart. In a small bowl, stir in 1 tablespoon of water into the cornstarch, then stir the mixture into the berry sauce and continue cooking, uncovered, until thickened, 2-3 minutes more. Remove from heat and cover to keep warm. Preheat a grill or grill pan to medium-low. Brush the pound cake slices with the melted butter. Grill until the cake is toasted, about 2 minutes on each side. Spread the warm sauce on dessert plates, place 2 cake slices on each plate and top with additional sauce.