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Spicy Tomato Sauce Onion Boil
375min
Total Time
6 people
Servings
Easy
Difficulty
Budget
Cost
120 kcal
Calories
Ingredients
6
- 8 large ripe tomatoes, roughly chopped
- 4 large yellow onions, thinly sliced
- 6 cloves garlic, minced
- 2 tablespoons olive oil
- 2 tablespoons red pepper flakes
- 2 teaspoons dried oregano
- 2 teaspoons dried basil
- 1 tablespoon tomato paste
- 2 bay leaves
- 1 teaspoon sugar
- Salt and black pepper to taste
Instructions
1
Layer sliced onions at the bottom of the crockpot
2
Add minced garlic and drizzle with olive oil
3
Place chopped tomatoes on top of the onions
4
Add tomato paste, red pepper flakes, oregano, basil, and bay leaves
5
Sprinkle sugar, salt, and black pepper
6
Cover and cook on LOW for 6-8 hours or HIGH for 3-4 hours
7
Stir occasionally if possible to ensure even cooking
8
Remove bay leaves before serving
9
Use an immersion blender if smoother consistency is desired
Troubleshooting
If sauce is too watery, remove lid and cook on HIGH for additional 30 minutes
If sauce is too thick, add small amounts of water or broth until desired consistency
If sauce is too acidic, add more sugar in small increments
If sauce lacks depth, add more tomato paste
If sauce is too spicy, add a small amount of cream or butter to mellow heat
Recipe Variations
Arrabbiata Style: Double the red pepper flakes
Vodka Sauce: Add cream and vodka in final hour
Garden Style: Add diced zucchini and carrots
Puttanesca: Include olives, capers, and anchovies
Roasted Garlic: Add whole roasted garlic bulb
Serving Suggestions
Serve over freshly cooked pasta
Use as pizza sauce base
Spread on homemade garlic bread
Use as dipping sauce for mozzarella sticks
Add to lasagna layers
Nutrition Facts
120
Calories
3g
Protein
18g
Carbs
5g
Fat
Common Mistakes to Avoid
Not slicing onions thinly enough for proper caramelization
Adding too much liquid which dilutes flavors
Forgetting to remove bay leaves before serving
Skipping the sugar which balances acidity
Over-blending which makes sauce too smooth
Frequently Asked Questions
How long does this sauce need to cook in the crockpot?
6-8 hours on LOW or 3-4 hours on HIGH for best results.
Can I use canned tomatoes instead of fresh?
Yes, use 2 28-oz cans of whole peeled tomatoes as a substitute.
Why add sugar to tomato sauce?
Sugar helps balance the natural acidity of tomatoes.
Can I freeze this sauce?
Yes, it freezes well for up to 6 months in airtight containers.
How do I make the sauce less spicy?
Reduce red pepper flakes or add cream to mellow the heat.
Can I double this recipe?
Yes, if your crockpot is large enough, but may need longer cooking time.
Why are my onions not caramelizing?
Ensure onions are sliced thinly and placed at bottom of pot.
How do I thicken the sauce?
Cook longer with lid off or add more tomato paste.
Can I add meat to this sauce?
Yes, brown meat separately first before adding to crockpot.
What's the best way to store leftover sauce?
In airtight containers in refrigerator for up to 5 days.
Reviews
Sofia R.
Apr 13, 2026
Perfect base sauce recipe! Love how the onions caramelize.
Marcus T.
Mar 20, 2026
Great flavor, though I added more garlic for extra kick.
Lucia P.
Mar 27, 2026
Best tomato sauce I've made in my crockpot!
Chen W.
Apr 12, 2026
Love how hands-off this recipe is. Great results!
Aisha K.
Mar 17, 2026
The slow cooking really develops the flavors beautifully.
