Dice the veggies and onion and set aside. In a large soup pot or Dutch oven, fry the ground sausage over medium-high heat until browned, stirring often. Remove from heat and drain any excess fat if needed (this will depend on the leanness of your sausage).
Return the pot to the heat, add the diced peppers, onions, and celery to the meat, and continue to cook until the vegetables are just tender-crisp, about 5 minutes, stirring often.
Next, add the diced tomatoes, beef broth (store-bought, homemade, or water and bouillon mixture – whatever you have on hand), Italian spice, and garlic powder to the pot. Increase the heat to high and bring the soup to a boil, watching carefully and stirring often. Once the soup reaches a boil, add the brown rice, then gradually reduce the heat to maintain a gentle simmer.
Continue simmering the soup, covered, for 30 minutes, stirring occasionally.
If desired, serve the soup topped with a sprinkle of cheddar cheese and a dollop of sour cream. For a complete meal, this soup is delicious served with fresh rolls or hearty bread and a garden salad.