Simple Roasted Crockpot Tomato Sauce Recipe

This Roasted Crockpot Tomato Sauce is made from scratch, flavorful, and packed with nutrition — without the added sugars, fillers, and preservatives often found in store-bought brands.

This sauce slow cooks in your crockpot with fresh or frozen whole tomatoes), veggies, fresh basil, balsamic vinegar, and plenty of garlic all roasted together and slow cooked to make a rich, hearty tomato sauce we know you’ll love.

After a bit of prep work, you can set it and let your crockpot simmer all day. Use this full-bodied red sauce in lasagna, spaghetti dinners, creamy ravioli, or even as an easy pizza sauce.

This sauce is a great way to turn a basket of ripe fruit and veggies into a freezer-friendly sauce you can enjoy all year long.

From Garden Tomatoes to Homemade Sauce

This recipe is a wonderful way to use fresh garden tomatoes when the harvest is coming in faster than you can eat them. Roasting the tomatoes first deepens their flavor and removes excess moisture, creating a rich base for a slow-simmered tomato sauce.

If you grow your own tomatoes, explore more harvest tips and garden recipes in our Garden & Greenhouse section.

What does roasting do to vegetables?

Roasting vegetables creates a deeper flavor and enhances the natural flavors of each veggie, drawing out the moisture and cooking the exterior to a crispy golden brown.

By roasting vegetables you can enjoy them in a variety of ways, either on their own as a side dish, paired with pastas and meats for a nutritious, flavor packed meal, or blended into a sauce which is our favorite way to use up extra vegetables.

This crockpot tomato sauce is a fantastic way to get the most out of your garden harvest.

Does Roasting Tomatoes Remove the Acidity?

Tomatoes are a highly acidic veggie making them difficult for some people to digest and enjoy. They often contribute to heartburn and acid reflux. Unfortunately roasting your tomatoes won’t make them less acidic.

Tomatoes acidity range from 4.1 to 4.6 for most varieties. If you struggle with heartburn or acid reflux it’s best to opt for other less acid sauces such as pesto or white cream sauces.

Things you can do to mask or slightly reduce the acidity of tomato sauces.

• Put a few carrots into the roasted vegetable mix. One to two carrots will help balance the acid in the tomatoes.
• Use Vidalia sweet onions rather than a stronger white or yellow onion. This will also mellow the acid in the final sauce.
• Add a pinch of baking soda (not too much or your sauce will taste bitter) to counteract the acidity of your finished tomato sauce.
• Adding sugar to tomato sauces is another technique used to reduce the acidity though it’s not something we choose to do.

You can add milk or cream to your sauce, this will mellow out the boldness of the acidity and mask it slightly.

Homemade recipes like this are unique and easily tailored to your family’s tastes. We are especially fond of roasting vegetables to enhance their flavors. Try our roasted vegetable recipe for an easy and healthy side dish.

If you’re Looking for more ways to use up fresh tomatoes these recipes are all winners.

How do you freeze Crockpot tomato sauce?

All homemade sauces freeze, or freeze dry, very well and can be available year round by making extra and setting some aside in your freezer. Follow these steps to store all of your scratch made sauces.

• Complete the roasted tomato sauce recipe as directed.
• Let the sauce cool to room temperature.
• Pour the sauce into quart sized Ziplock freezer bags or other freezer safe containers.
• Label with the recipe name and date.
• Freeze for 3-4 months.

Can You Make Tomato Sauce with Frozen Tomatoes?

Yes! Frozen whole tomatoes work very well in this recipe. Simply thaw the tomatoes in a colander so excess liquid can drain, then slip off the skins before roasting.

If you preserve your harvest this way, you can pull frozen tomatoes straight from the freezer and turn them into homemade sauce whenever you need it. Learn more about how to freeze whole tomatoes for cooking in our preservation guide.

Recipe Notes:

This crockpot tomato sauce is simple and so rich and creamy! All it takes is a little bit of planning and few hours in your crockpot to simmer to perfection. You will roast the fresh tomato-vegetable mixture for about an hour.

If Using frozen whole tomatoes: Thaw in a colander, slip off skins, and drain well before roasting. Frozen tomatoes release more liquid, so you may need extra tomato paste or a longer roast for a thicker sauce.

Then blend it all up and transfer it to your slow cooker for the rest of the afternoon. Simple! And your house will smell fantastic all day.

The Process:

First, preheat your oven to 425 degrees F.

Preparing the Vegetables:

• Chop your tomatoes. Roma tomatoes are an excellent choice for sauces.
• Quarter them and lay them down in the pan.
• Rough chop your onion, dropping the pieces over top of the tomatoes.
• Chop peppers and arrange them in your baking dish with the onion and tomato chunks.
• Add your whole cloves of garlic. Place them among the onions, peppers and tomatoes.
• Tear a few fresh basil leaves and sprinkle them around.
• Drizzle the mixture with some olive oil, sea salt and fresh ground pepper.
• Using your hands, mix it all around to coat everything.

The Roasting Process:

Place the prepared vegetables in your preheated oven for 45 minutes to an hour.

Your home will smell incredible while these veggies roast.

Puree the Vegetables:

• Once all are soft and slightly caramelized cool them and blend into a puree.
• Spoon the roasted vegetables into your food processor or blender. (do this in small batches if necessary)
• Add the can of tomato paste and 1 tablespoon of balsamic vinegar.
• Blend to a smooth, creamy consistency. You can add some of the juices from the baking dish if you would like to thin it out.

If you don’t have a blender or prefer not to use one you can run the finished sauce through a foly food mill once it is finished slow cooking. The result is the same. A yummy smooth rich crockpot tomato sauce.

Slow Cook:

Any slow cooker will work. Today there are so many different multi cookers in our kitchens. If they slow cook you can make this crockpot tomato sauce recipe in them.

Instant Pot Tomato Sauce:

To make this pasta sauce recipe in your instant pot. Use the slow cook function and follow the instructions in this recipe exactly.

I use my instant pot for slow cooking, I recommend cooking on medium heat as they cook slightly lower than most crock pots.

Finishing:

At this point add any extra spices you prefer. We love extra oregano and a bit of dried rosemary. 

The basil and garlic are the mvps of this recipe.

Additional ideas for this recipe

• Add browned meat to your slow cooker when you pour in the roasted puree.
• Add 1 pound of browned Italian sausage to the cooker. We enjoy sausage in our 5 Cheese Homemade Lasagna.
• Ground beef also makes a nice addition to this slow cooker tomato sauce. 
• Add chopped mushrooms or spinach in the last hour of simmering to bump up the texture and nutritional benefits.
• Refresh any dried spices in the last 30 minutes of simmering to keep the flavors powerful.
• Red pepper flakes, fresh rosemary leaves and fresh oregano all make great enhancements to this recipe.

How to Store Homemade Tomato Sauce

This roasted crockpot tomato sauce stores beautifully, making it perfect for meal prep and garden harvest preservation.

You can store this sauce several ways:

• Refrigerate: Keep in airtight containers for up to 5 days.
• Freeze: Portion the sauce into freezer containers or bags for easy weeknight meals.
• Freeze Dry: Freeze-drying is another excellent long-term storage option for homemade sauces.

If you’re exploring different preservation methods, visit our Freeze Drying section for more ideas and guides.

Our family enjoyed this over whole grain pasta for a simple, filling dinner.

What to Make with Crockpot Tomato Sauce

Once you have a batch of homemade tomato sauce ready, dinner becomes easy. This sauce works beautifully in classic comfort meals like pasta dishes, baked casseroles, and hearty soups.

Try using this sauce in recipes like:

• Easy Homemade Marinara Sauce
• Roasted Pepper Tomato Soup
• Five Cheese Lasagna
• Browse more meal ideas in our Weeknight Dinners collection.

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