This Slow Cooker Spaghetti Sauce with Fresh Tomatoes is one of my favorite ways to use an abundance of garden tomatoes. Fresh vine-ripened tomatoes slow cook with garlic, onion, Italian seasoning, and tomato paste for 6 to 8 hours, creating a rich homemade spaghetti sauce with very little hands-on work.
This recipe makes about 10 cups of sauce, which is enough to feed a large family or divide into containers and freeze for the winter months.
I grow a lot of tomato plants in my garden because we love fresh tomatoes on sandwiches and salads, but I especially look forward to using them for homemade tomato soup and spaghetti sauce. By late summer, when the garden is producing tomatoes faster than we can eat them, I almost always have my slow cooker going with a batch of this sauce.
This freezer-friendly spaghetti sauce recipe is an easy way to preserve some of that fresh garden tomato flavor to enjoy long after tomato season is over.
Why You’ll Love This Recipe
- Perfect for garden tomatoes: A great way to use several pounds of ripe tomatoes at once.
- Mostly hands-off: Once everything is in the slow cooker, it does most of the work for you.
- Great for freezing: Make a large batch now and enjoy homemade spaghetti sauce throughout the winter.
- Simple ingredients: Fresh tomatoes, herbs, garlic, onion, and a few pantry staples are all you need.
- Versatile: Use it for spaghetti, lasagna, baked pasta, eggplant Parmesan, or anywhere you would normally use a tomato-based pasta sauce.
Ingredients
Fresh tomatoes: You’ll need about 6 pounds of ripe tomatoes. Garden-fresh or locally grown vine-ripened tomatoes will give you the best flavor. Roma or plum tomatoes are especially good because they contain less water, but I generally use whatever ripe tomatoes are coming out of my garden.
Tomato paste: One 6-ounce can adds concentrated tomato flavor and helps give the sauce a richer, thicker consistency.
Onion: About 1 cup chopped onion adds flavor as it slowly cooks.
Garlic: Use 4 to 5 fresh garlic cloves, or about 1 tablespoon minced garlic.
Italian seasoning: 1½ tablespoons adds plenty of herb flavor during the long cooking time. I like to use my Homemade Italian Seasoning blend.
Sugar: One tablespoon helps balance the natural acidity of the fresh tomatoes. You can adjust this depending on the sweetness of your tomatoes.
Salt and pepper: Start with ½ teaspoon salt and black pepper to taste. You can always adjust the seasoning after the sauce has cooked.
Fresh herbs: I like to use 1 to 2 tablespoons of chopped fresh basil, parsley, oregano, or a combination. Adding the fresh herbs toward the end helps preserve their bright, fresh flavor.
You will also need an 8-quart or larger Slow Cooker for this recipe.
How to Make Spaghetti Sauce in the Slow Cooker
- Peel the tomatoes: Bring a large pot of water to a simmer. Using a slotted spoon, carefully lower several tomatoes into the water and simmer for about 30 seconds to 1 minute, or until you see the skins begin to split or pull away from the tomatoes.
Remove the tomatoes with the slotted spoon and transfer them to a large bowl of ice water. Repeat with the remaining tomatoes, working in batches. The ice water stops the cooking process and quickly cools the tomatoes, making them easier to handle.
Once they’re cool enough to handle, remove the tomatoes from the ice water. Using a paring knife, remove the stem, core, and peel from each tomato. - Cut the tomatoes: Cut the peeled tomatoes into quarters and add them directly to the slow cooker.
- Add the remaining ingredients: Add the chopped onion, garlic, Italian seasoning, tomato paste, sugar, salt, and pepper to the slow cooker. Stir everything together as well as you can. The tomatoes will release plenty of liquid as they cook.
- Slow cook: Cover and cook on LOW for 6 to 8 hours, stirring occasionally if you’re around. The tomatoes will break down and the flavors will deepen as the sauce slowly cooks.
- Blend the sauce: At the end of cooking, add the fresh basil, parsley, oregano, or your favorite combination of fresh herbs. Use an immersion blender to puree the sauce directly in the slow cooker until it reaches your preferred consistency. You can leave it slightly chunky or blend until completely smooth.
Taste and adjust the salt, pepper, or sugar as needed. - Serve over your favorite pasta and enjoy!
Note: Don’t be surprised if the slow cooker looks very full when you first add the tomatoes. They will cook down considerably over the 6 to 8 hours, reducing by about half and yielding approximately 10 cups of sauce.
Storage and Freezing
Allow the spaghetti sauce to cool before transferring it to airtight containers. Store it in the refrigerator for up to 4 days.
For longer storage, divide the cooled sauce into freezer-safe containers, leaving a little room at the top for expansion, and freeze. I like freezing it in meal-sized portions so I can pull out exactly what I need for an easy dinner during the winter. Freeze for up to 6 months. Defrost in the refrigerator overnight when ready to use.
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Note: This recipe has not been tested for canning and is intended for refrigerator or freezer storage only.
Technically, you can leave the skins on, especially since the sauce will be blended. However, peeling the tomatoes gives the finished sauce a smoother texture, and blanching makes the skins very easy to remove.
Roma or plum tomatoes are ideal because they have fewer seeds and less water. However, this recipe is also a great way to use a mixture of ripe garden tomatoes which is what I do since I plant a variety in my garden.
Yes. This sauce freezes very well and is one of my favorite ways to preserve fresh tomatoes from the garden. Let the sauce cool completely before portioning it into freezer-safe containers.
Fresh tomatoes vary considerably in water content. If your sauce is too thin, cook it uncovered toward the end to allow some of that extra moisture to evaporate.
A Few Final Thoughts
There is nothing quite like homemade spaghetti sauce made with freshly picked tomatoes. It’s one of those recipes I look forward to every tomato season, especially knowing I’ll have containers tucked away in the freezer for easy dinners throughout the winter.
If you want more ways to use fresh tomatoes, check out these recipes: Roasted Tomato Soup, and Roasted Cherry Tomato Bruschetta.
For other slow cooker or crockpot recipes, check out my Slow Cooker Applesauce, and my Crockpot Vegetarian Chili .
This post may contain affiliate links by which I may receive a small commission. All product links are items I personally use in my kitchen.
If you make this recipe I would love it if you left a review below and tag me on Instagram!
Slow Cooker Spaghetti Sauce with Fresh Tomatoes
Equipment
- Slow Cooker (Crockpot) 8 quarts
Ingredients
- 6 pounds fresh tomatoes
- 1 cup chopped onion
- 1 tablespoon garlic, chopped fine about 4-5 cloves
- 1½ tablespoons dried Italian seasoning
- 6 ounces tomato paste
- 1 tablespoon sugar
- ¾ teaspoon salt additional as needed
- ¼ teaspoon black pepper additional as needed
- 1-2 tablespoons fresh herbs – basil, parsley, oregano
Instructions
- Bring a large pot of water to a simmer. While pot comes to a simmer, make a small "X" shape into the bottom of each tomato.
- Using a slotted spoon, carefully lower several tomatoes into the water and simmer for about 30 seconds to one minute, or until you see the skins begin to split or pull away from the tomato.
- Using the slotted spoon, transfer the tomatoes to a large bowl of ice water. Repeat with remaining tomatoes, working in batches. The ice water stops the cooking process and quickly cools the tomatoes, making them easier to handle.
- Once cool enough to handle, remove the tomatoes from the ice water. Using a pairing knife, remove the stem and core from each tomato, while peeling away the skins (they should lift off easily).
- Cut the peeled and cored tomatoes into quarters and add to the slow cooker bae.
- Add chopped onion, garlic, Italian seasoning, tomato paste, sugar, salt, and pepper. Stir everything together.
- Cover and set it to LOW for 6-8 hours. Or High for 3-4 hours. The tomatoes will release liquid as they cook.
- At the end of cooking, add the fresh herbs.
- Use an immersion blender to puree the sauce directly in the slow cooker until it reaches your preferred consistency. Or you can choice to leave sauce chunky.
- Adjust seasonings to taste. Them serve and enjoy!
