Preheat the oven to 350ºF. Sprinkle the cheese onto the piecrust. In a skillet, heat the oil and sauté the onion, green pepper, garlic, tomato, olives, and corn until tender. Add the chili powder, cumin, oregano, and salt and pepper and stir to blend. Spread the vegetables over the cheese in the piecrust. In a separate bowl, beat the eggs until frothy, add the cream and beat to blend. Pour the egg mixture over the vegetables. Bake for 1 hour and 10 minutes, or until the eggs are firm in the center. Let stand for 10 minutes. Garnish with dollops of sour cream mixed with picante sauce.