Preheat oven to 325 degrees F. Grease a 13x9x2-inch baking pan; set aside. In a medium bowl, stir together flour, mace, and salt; set aside.
In a large bowl, beat the 1 cup butter with an electric mixer on medium to high speed for 30 seconds. Add brown sugar and the 1- 1/3 cups granulated sugar. Beat until combined, scraping side of bowl occasionally. Beat in eggs until combined. Alternately add flour mixture and wine to butter mixture, beating on low speed after each addition just until combined. Stir in pecans. Pour batter into the prepared baking pan, spreading evenly. Sprinkle with 2 cups of the grapes.
Bake for 40 minutes. Sprinkle with the remaining 1 cup grapes. Bake about 40 minutes more or until a toothpick inserted in the center comes out clean.
Immediately brush hot cake with the 2 tablespoons melted butter and sprinkle with the 1 tablespoon granulated sugar. Cool in pan on a wire rack. Makes 20 servings.