Vegetarian Slow Cooker Spaghetti Sauce
2 Comments Jan 12, 2022
Updated May 28, 2025
This post may contain affiliate links. Please read our disclosure policy.
This recipe for vegetarian slow cooker spaghetti sauce will leave your family happy and satisfied. You can make this easy dish for any occasion, as it tastes great with any noodles or rice and is easy to make for a crowd.
This recipe is excellent for meatless Monday! Try my Slow Cooker Spaghetti Sauce, Bolognese Sauce, or Slow Cooker Chicken Spaghetti recipes if you need a different sauce.
It’s perfect to use up those cans of tomatoes you have sitting around in the pantry, so go ahead and dig them out! This recipe requires less than 10 minutes of prep time before going into the crockpot to cook all day long. This recipe is similar to the Italian recipe Peperonata, which is filled with sweet bell peppers.
When you get home from work, the only thing left is to make your favorite pasta on the stovetop, then serve over cooked pasta.
Recipe Ingredients
- Vegetables – Three bell peppers, onion and garlic.
- Canned Tomatoes – Tomato paste, tomato sauce and diced tomatoes will make a perfect texture for the base of your sauce.
- Seasonings – Italian seasoning, salt, pepper and red pepper flakes.
- Sugar – This makes all the difference, we aren’t adding much but just enough to take the acidity from the sauce. You’d be surprised to know that almost every store bought sauce has a touch of sugar.
Step-by-Step Directions
Step One – Add everything to the crockpot.
Step Two – Stir. Cook on HIGH for 4 hours or on low for 6 hours. Serve and enjoy!
Cook’s Notes
Adding sugar to a pasta sauce may sound odd, but it offers a layer of complexity that you wouldn’t get otherwise.
Add 1/4 cup of red wine (such as pinot noir or Cabernet Savignon) to this recipe at the beginning of the cooking time. Be sure to tell your guests that there is wine in the sauce for the alcohol doesn’t cook out completely.
How to serve vegetarian spaghetti sauce
- You can serve slow cooker three pepper pasta sauce with cooked noodles of your choice, or even rice to pair the meal with.
- This dish is also great for dipping bread and garlic toast in, or even topping a sandwich!
- Serve with a green salad if desired.
Vegetarian Slow Cooker Spaghetti Sauce
Ingredients
- 3 bell peppers, yellow, red and green bell pepper, cut into 1-inch pieces.
- 1 small yellow onion, diced
- 29 oz. diced tomatoes, (two 14.5-oz. cans)
- 6 oz. tomato paste
- 8 oz. tomato sauce
- 1 Tbsp. Italian seasoning
- 2 minced garlic cloves, (about one tablespoon)
- 1/2 tsp. sea salt
- 1/4 tsp. red pepper flakes, omit if you don't want any heat
- 1 Tbsp. sugar,
Instructions
- Cut peppers and onions and place in crockpot.
- Add remaining ingredients and stir well.
- Cover and cook on high for 4 hours or on low for 6 hours.
- Serve over any type of pasta, enjoy!
Nutrition
Nutrition info is auto-generated. This information is an estimate; if you are on a special diet, please use your own calculations.
More Vegetarian Slow Cooker Recipes
Looking for more slow cooker inspiration? Try Slow Cooker Zucchini Bolognese for a veggie-packed pasta night, or go meat-free with Jackfruit Pulled Pork.
For hearty plant-based options, Slow Cooker Chickpeas and Slow Cooker Vegetarian Chili are both filling and flavorful. Or try my slow cooker marinara sauce that is great for freezing for later.
And for something cozy, you can’t go wrong with Slow Cooker Butternut Squash Soup.
This sauce did not have any flavor at all! I followed the directions exactly. I ended up with a five star sauce only because I added a lot more of the seasoning that was in the recipe. The diced tomatoes I bought did not have any Italian seasoning in it. I don’t know if it comes that way upfront, so maybe that was the problem. I will try to make it again and look for diced tomatoes with some type of Italian seasoning included in the can. I would assume that would make a huge difference. Wish me luck!