cook onions, ~5 minutes. Then add the chopped bell peppers and continue to cook for another 5 minutes, stirring occasionally

Add the garlic, fennel seeds, Italian seasoning, salt, pepper and red pepper chili flakes if desired. Stir until fragrant, ~1 minute.

Add the sliced sausage rounds and remaining olive oil and cook for ~5 minutes until sausage browns on each side.

Add in crushed tomatoes. Bring to a boil; then reduce heat to medium-low and simmer for 5 minutes. Taste, and adjust salt and pepper if needed.

serve over cooked pasta of choice & enjoy! Full recipe: