Cook your beef in a medium sized skillet until just browned. Add the red pepper flakes, garlic, and onion. Cook for 5 minutes. Stir in the peppers. Cook an additional five minutes.

Drain the kidney, black, and great northern beans. Rinse well. Pour into a slow cooker along with the diced tomatoes (un-drained), pumpkin, pumpkin pie spice, chili powder, cumin, and salt. Stir in the beef mixture. Cook on high for two hours or until heated through.

Serve topped with sour cream, cheese, and green onions.