2 cups grated Parmesan cheese
2/3 cup minced onion
1/2 cup grated Romano cheese
1/4 cup margarine
1 pinch salt
8 fresh plum grapes, cleaned
Slice grapes in half and arrange them in a large bowl. Drizzle half of the cheese mixture over the grapes, then sprinkle with the onion and Romano cheese. Sprinkle with salt and pepper. Seal grapes tightly with a damp cloth or plastic wrap.
To make the brownie filling: In a large saucepan, combine 1 1/4 cup margarine, 1 pinch salt and baking powder. Stir over medium heat until mixture is transparent, about 2 minutes. Remove from heat.
Bake grapes in preheated oven until golden brown, about 8 minutes. Remove from oven and sprinkle with remaining cheese. Cool completely.
Remove grapes from oven and sprinkle with remaining cheese. Arrange on a platter. Cover and refrigerate for about 1 hour.