Short description
These slow cooker stuffed peppers simmer gently in a rich homemade marinara sauce until perfectly tender. Filled with black beans, quinoa, and zucchini, they’re hearty, healthy, and completely plant-based—ideal for a comforting dinner with minimal effort.
Why You’ll Love This Recipe
- Slow cooker convenience—just set it and let it cook.
- A flavorful homemade marinara sauce doubles as both cooking liquid and serving sauce.
- Nutrient-packed filling with protein-rich beans, quinoa, and vegetables.
- Vegetarian and easily made vegan.
- Perfect for meal prep or a cozy family dinner.

Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
For the marinara
1 (28-ounce) can crushed tomatoes
1 (28-ounce) can diced tomatoes (with juices)
1 (6-ounce) can tomato paste
1 medium yellow onion, diced
2 ½ teaspoons minced garlic (about 5 cloves)
2 bay leaves
1 tablespoon dried basil
1 tablespoon packed brown sugar
1 tablespoon balsamic vinegar
1 ½ teaspoons dried oregano
½ teaspoon red pepper flakes
1 teaspoon salt
½ teaspoon freshly ground black pepper
For the stuffed peppers
4 medium bell peppers (any color), tops sliced off and seeds removed
2 (15-ounce) cans black beans, drained and rinsed
½ cup uncooked quinoa, rinsed
2 medium zucchini, chopped
Directions
- In a slow cooker, combine crushed tomatoes, diced tomatoes with juices, tomato paste, onion, garlic, bay leaves, basil, brown sugar, balsamic vinegar, oregano, red pepper flakes, salt, and black pepper. Stir well.
- Remove 1 ½ cups of this marinara mixture and set aside.
- Prepare the bell peppers by slicing off the tops and removing seeds and membranes. Place them cut-side up in the slow cooker over the sauce.
- In a bowl, mix black beans, quinoa, zucchini, and the reserved marinara sauce.
- Stuff each bell pepper with the filling and place back into the slow cooker.
- Cover and cook on low for 6 hours, until peppers are tender and filling is cooked through.
- Serve hot with extra marinara sauce spooned over the top.
Servings and timing
Serves 4.
Preparation time: 20 minutes.
Cooking time: 6 hours (low setting).
Total time: about 6 hours 20 minutes.
Variations
- Add shredded cheese on top of each pepper before serving for extra richness.
- Swap quinoa with rice, couscous, or bulgur.
- Add chopped spinach, mushrooms, or corn to the filling for extra veggies.
- Use lentils instead of black beans for a different texture.
- Spice it up with extra chili flakes or a dash of hot sauce.
Storage/Reheating
Refrigerate leftovers in an airtight container for up to 4 days.
Freeze cooked stuffed peppers (individually wrapped) for up to 2 months. Thaw overnight in the fridge before reheating.
Reheat in the oven at 350°F (175°C) until warmed through, or microwave in short intervals.

FAQs
1. Can I cook these on high instead of low?
Yes, cook on high for 3–4 hours instead of low for 6 hours.
2. Do I need to pre-cook the quinoa?
No, it cooks inside the peppers as they simmer in the sauce.
3. Can I make this recipe vegan?
Yes, it’s naturally vegan as written—just skip any optional cheese toppings.
4. Can I use frozen peppers?
Fresh peppers are best, but thawed frozen peppers can work if drained well.
5. Can I use other beans instead of black beans?
Yes, kidney beans, cannellini beans, or chickpeas are great substitutes.
6. How do I stop the peppers from falling over in the slow cooker?
Arrange them snugly together so they support each other.
7. Can I use store-bought marinara sauce?
Yes, but making the sauce in the slow cooker adds richer flavor.
8. What sides go well with stuffed peppers?
They pair beautifully with garlic bread, a fresh salad, or roasted vegetables.
9. How do I make the peppers spicier?
Add extra red pepper flakes, chili powder, or diced jalapeños to the filling.
10. Can I meal prep this dish?
Yes, assemble peppers with filling and refrigerate overnight before cooking the next day.
Conclusion
Slow cooker stuffed peppers in marinara sauce are a wholesome, hearty, and flavorful meal that cooks effortlessly. With tender peppers, a savory bean-quinoa filling, and a rich tomato base, they make a perfect family dinner or meal-prep option. Serve with bread or salad for a complete and satisfying dish.
Print
Slow Cooker Stuffed Peppers in Marinara Sauce
- Total Time: 6 hours 20 minutes
- Yield: 4 servings
- Diet: Vegan
Description
These slow cooker stuffed peppers simmer gently in a rich homemade marinara sauce until perfectly tender. Filled with black beans, quinoa, and zucchini, they’re hearty, healthy, and completely plant-based—ideal for a comforting dinner with minimal effort.
Ingredients
1 (28-ounce) can crushed tomatoes
1 (28-ounce) can diced tomatoes (with juices)
1 (6-ounce) can tomato paste
1 medium yellow onion, diced
2 ½ teaspoons minced garlic (about 5 cloves)
2 bay leaves
1 tablespoon dried basil
1 tablespoon packed brown sugar
1 tablespoon balsamic vinegar
1 ½ teaspoons dried oregano
½ teaspoon red pepper flakes
1 teaspoon salt
½ teaspoon freshly ground black pepper
4 medium bell peppers, tops sliced off and seeds removed
2 (15-ounce) cans black beans, drained and rinsed
½ cup uncooked quinoa, rinsed
2 medium zucchini, chopped
Instructions
- In a slow cooker, combine crushed tomatoes, diced tomatoes with juices, tomato paste, onion, garlic, bay leaves, basil, brown sugar, balsamic vinegar, oregano, red pepper flakes, salt, and black pepper. Stir well.
- Remove 1 ½ cups of this marinara mixture and set aside.
- Prepare the bell peppers by slicing off the tops and removing seeds and membranes. Place them cut-side up in the slow cooker over the sauce.
- In a bowl, mix black beans, quinoa, zucchini, and the reserved marinara sauce.
- Stuff each bell pepper with the filling and place back into the slow cooker.
- Cover and cook on low for 6 hours, until peppers are tender and filling is cooked through.
- Serve hot with extra marinara sauce spooned over the top.
Notes
- Add shredded cheese on top of each pepper before serving for extra richness.
- Swap quinoa with rice, couscous, or bulgur.
- Add chopped spinach, mushrooms, or corn to the filling for extra veggies.
- Use lentils instead of black beans for a different texture.
- Spice it up with extra chili flakes or a dash of hot sauce.
- Prep Time: 20 minutes
- Cook Time: 6 hours
- Category: Main Dish
- Method: Slow Cooking
- Cuisine: Italian-Inspired
Nutrition
- Serving Size: 1 stuffed pepper
- Calories: 310 kcal
- Sugar: 11 g
- Sodium: 620 mg
- Fat: 4 g
- Saturated Fat: 0.5 g
- Unsaturated Fat: 3 g
- Trans Fat: 0 g
- Carbohydrates: 53 g
- Fiber: 13 g
- Protein: 15 g
- Cholesterol: 0 mg