Brown the Ground Beef: In a large soup pot or Dutch oven, cook the ground beef over medium-high heat until it’s browned and fully cooked, breaking it up with a spoon as it cooks. Drain off any excess grease if needed, then season lightly with salt and pepper.
Sauté the Vegetables: Add the chopped onion, green bell pepper, and red bell pepper to the pot. Cook for about 4–5 minutes, stirring occasionally, until the vegetables are softened and fragrant. This helps build flavor and brings out the natural sweetness of the peppers.
Add the Liquids and Tomatoes: Stir in the tomato sauce, diced tomatoes (with their juices), and beef broth. Mix well to combine all the ingredients. Bring the mixture to a boil over medium-high heat.
Simmer the Soup: Once it reaches a boil, reduce the heat to low. Cover the pot and let the soup simmer gently for about 20–25 minutes, allowing the flavors to meld together and the peppers to become tender.
Add the Rice: Stir in the cooked rice, mixing until evenly distributed. Let it warm through for another 3–5 minutes. If you prefer a thinner soup, add an extra splash of beef broth; for a thicker, stew-like texture, use a bit less.
Season to Taste: Taste the soup and adjust the seasonings with additional salt and pepper as needed. For a bit of heat, you can also add a pinch of red pepper flakes or smoked paprika.
