Bring stock to a boil, sprinkle in cornmeal and cook over low heat for 15 minutes while stirring. Season polenta with salt and pepper and spread half onto a greased baking sheet to a 1/3 inch thickness. Let cool.
Rinse tomatoes and cut into quarters. Cut olives into rings. Peel garlic and slice thinly.
Heat oil in a small pain and sauté garlic over low heat for 3 minutes until translucent. Then mix immediately with tomatoes and olives.
Rinse basil and cut into thin strips. Mix with tomatoes. Slice mozzarella and drain between 2 layers of paper towel.
Cut polenta into 8 pieces to fit into cooking trays. Pour tomato mixture over the top, season with salt and pepper, and top with mozzarella. Sprinkle with Parmesan and cook under the heating element for 10-15 minutes.