Heat a large skillet over medium and coat with olive oil. Add the sausage links and brown for 2-3 minutes per side until golden. Add to the slow cooker base.
Slice the peppers and onion and add those to the slow cooker.
Mix the garlic, crushed tomatoes, marina sauce, Italian seasoning, oregano, salt, pepper and red pepper flakes together in a bowl. Pour the sauce over the sausage and vegetables.
Secure the slow cooker base and cook for 3-4 hours on high or 5-6 hours on low.
About 15 minutes before serving, remove the lid. Take out the sausage and slice each link. Place back into the slow cooker, leaving it uncovered for the sauce to thicken. Taste test the sauce and adjust the seasoning as necessary.
Serve the sausage and peppers in a roll or plated.
Notes
Don’t skip browning the sausage, it adds a lot of flavor and helps keep the shape while slow cooking. If you want to serve the sausage as links, just skip the slicing step.
We used mild Italian sausage, but you can use sweet or hot. Whatever you prefer.
This is a great dish to meal prep with. You can double the recipe and have it for lunches or dinners. You can serve it over pasta or mashed potatoes to switch up the meal.
You can stir the sauce and vegetables about halfway through to help it all come together.