Lisa's Mexican Casserole

1/2 lb ground beef (browned, drained and rinsed) 1 tsp olive oil 1 green pepper 1 small onion 1 tbsp garlic minced 1 can black beans drained and rinsed 15 ounce can of tomato sauce 15 ounce can of Ro-tel tomatoes with chilies 1 cup frozen corn, cooked and drained 1 pkg taco seasoning 1 pkg ranch dressing powder 1/2 cup cheddar cheese 1/2 cup fat free sour cream 10 corn tortillas Preheat oven to 400, spray 9x13 glass pan with PAM. Brown Meat, drain and rinse. Cook meat longer to evaporate water. Meanwhile Saute Onion & Pepper in oil till soft, add garlic and saute for 3-4 more minutes making sure not to burn garlic. Also microwave the corn in a safe dish, drain when no longer frozen. Add all together in a large mixing bowl. Add remaining ingredients except cheese, sour cream and tortillas. Line baking dish with 5 tortillas, add half the mixture & dollop half sour cream on top, repeat once more except top with cheese. Bake in oven for about 30 minutes covered, 10 minutes uncovered till cheese is melted. It was way yummy, makes 6 big servings @ 5.4 pts per serving!