Italian Sausage and Peppers

Ingredients

• olive oil, divided
• small white or yellow onion, chopped
• bell peppers, chopped - multicolors
• garlic, crushed
• fennel seeds
• Italian seasoning
• kosher salt
• freshly ground black pepper, to taste
• red pepper chili flakes
• package Italian chicken sausage, sliced into rounds
• can crushed tomatoes
• Cooked Spaghetti