Slow Cooker Spaghetti Sauce

Overhead view of spaghetti with slow cooker meat sauce, cooked pasta, and serving spoon.

This easy slow cooker spaghetti sauce simmers all day with tomatoes, vegetables, garlic, and Italian herbs for rich, homemade flavor. Makes a big batch so you can freeze the extras for quick and easy dinners later.

Course Sauce

Cuisine Italian American

Prep Time 20

Cook Time 8

Total Time 8 20

Servings ½ cup servings

Calories 53kcal

Author Marye Audet-White

Ingredients

1 tablespoon olive oil
2 cups onion diced
1 cup carrots finely diced
1 cup celery finely diced
1 cup bell peppers diced
6 cloves garlic minced
25 ounces San Marzano whole peeled tomatoes
25 ounces crushed tomatoes
25 ounces tomato sauce
3 tablespoons dried oregano
2 tablespoons Italian seasoning
1 ½ teaspoons garlic powder
1½ teaspoons kosher salt plus more to taste
1 teaspoon black pepper
4 tablespoons brown sugar optional

Instructions

Heat the olive oil in a large skillet over medium heat. Add the onion, carrots, celery, and bell pepper. Cook for 7 to 10 minutes, stirring occasionally, until the vegetables have softened and the onion is translucent.
Add the minced garlic and cook for about 30 seconds, just until fragrant. Don't brown it.
Transfer the vegetables to a 6-quart slow cooker.
Add the San Marzano tomatoes, crushed tomatoes, tomato sauce, oregano, Italian seasoning, garlic powder, salt, and pepper. Crush the whole tomatoes with your hands as you add them, or break them up with a wooden spoon once they're in the Crockpot.
Stir everything together. Cover and cook on LOW for 8 hours.
Stir well and taste. Adjust the salt and pepper. Only add the brown sugar if the tomatoes still taste more acidic than you want, starting with a tablespoon.
Check the consistency. If it's thinner than you want, remove the lid and cook on HIGH for 30 to 60 minutes, stirring occasionally, until it reaches the consistency you like.

Notes

Storage:

Let the spaghetti sauce cool to room temperature before storing it, then refrigerate it in an airtight container for 3 to 4 days. For longer storage, freeze it in meal-size portions for up to 3 months. Leave a little room for expansion if you're using containers, or freeze it flat in freezer bags to save space.

Shortcut: Add the onion, carrots, celery, garlic, and bell pepper to a food processor and pulse until finely minced. Skip the sautéing and add the vegetables directly to the slow cooker with the remaining ingredients.

Tips:

You can add cooked ground beef or Italian sausage to the slow cooker if you want. I prefer to leave it out so I can use it in a variety of dishes.
An 8 ounce can of tomato paste will make it even richer and thicker but it's not necessary.

Nutrition