Pepperoni Polenta Pizza

-from SELF magazine

Makes 6 slices.
1/2 cup instant plain polenta
1/2 tsp salt
1/2 cup thinly sliced onion
1/4 cup diced red and/or green bell pepper
2 tsp olive oil
1/2 cup prepared marinara sauce
10 slices reduced-fat pepperoni
1/3 cup seeded and diced tomato 
1/4 tsp dried oregano
1/2 cup shredded reduced-fat (part skim) mozzarella
Preheat oven to 450°F. For crust, bring 2 1/4 cups water to a boil. Whisk in polenta and salt. Reduce heat and whisk 3 to 5 minutes or until thick. Pour into a 9" pie plate or cake tin, cover with plastic wrap and put in fridge to chill to room temperature. Meanwhile, sauté onion and pepper with oil in a nonstick skillet until onion is soft, about 2 minutes. Pour marinara sauce over crust. Add onion, pepper, pepperoni, tomato, and oregano; salt and pepper to taste. Bake 8 to 10 minutes. Sprinkle cheese on top and cook 2 more minutes or until cheese melts. Cut into 6 slices; serve immediately.