Chop onion, garlic, and bell pepper.

In a skillet, saute onion and pepper in oil until tender. Add chili powder, garlic, cumin, and pepper. Saute for one more minute.

Add tomatoes and bring to a boil.  Reduce heat, cover and simmer for 5 minutes.

Stir in beans and corn. Heat through. Transfer to a 11X7X2 inch baking dish.

For topping, combine topping ingredients in a small bowl.  Spoon over filling and spread where possible.

Bake at 375 for 20-25 minutes, or until filling is bubbly, and topping is cooked through (insert a toothpick to check).

Serve with salsa and sour cream if desired.