HEAT oven to 350°F.
HEAT a large oven-safe skillet over medium-high heat and add sausage, cook until golden.
ADD garlic, onion and bell peppers. Lower heat to medium and stir until vegetables are soft.
COOK tortellini by following package instructions.
STIR in cooked tortellini, oregano, marinara sauce and one cup of cheese.
TOP with remaining cheese. Bake in the oven for about 10 minutes until cheese is melted and bubbly.