Spicy Slow Cooker Pumpkin Chili

Name: Spicy Slow Cooker Pumpkin Chili
Cuisine: American, TexMex
Ingredients: 1 pound lean ground beef or turkey; 1 medium onion (chopped); 1 can diced tomatoes; 1 can fire roasted tomatoes; 1 can tomato sauce; 1 15 ounce can pumpkin puree (not pumpkin pie filling); 1 can red kidney beans; 1 can black beans; 1 tsp pumpkin pie spice; 2-3 tbsp chili powder; 1/2 tsp red pepper flakes; 1 tsp cumin; 1 red and yellow bell pepper (chopped); Pinch of salt and pepper; Garnish with sour cream and cheddar cheese