Sauce- Blend tomatoes with onion in blender. Pour in medium saucepan. Add pepper, salt and tomato paste. Heat until boiling, then simmer 5 to 10 minutes. Place 3 tortillas in bottom of crock pot. Layer on tortillas 1/3 of ground beef, 1/3
tomato sauce and 1/3 cheddar cheese, then 3 more tortillas. Repeat each layer 2 more times, ending with cheese. Cover and cook on low 6 to 8 hours.