Chunky Tomato Basil Soup with Baking Soda
A rustic tomato soup built on caramelized onions and fresh basil, finished with baking soda for brightness and silky texture. Canned whole tomatoes deliver concentrated flavor with minimal effort. The baking soda trick neutralizes acidity and creates a subtle foam that mellows the soup's tang. Serve hot with Parmesan for weeknight comfort or casual entertaining. This version prioritizes chunky texture and straightforward technique over blending.
Ingredients
- 2 tablespoon olive oil
- 2 medium yellow onion, chopped
- 8 clove garlic, minced
- 2 ½ ounce fresh basil leaf, chopped
- dried basil, 1.5 teaspoon substitute(optional)
- 3 28-ounce can whole peeled tomato, with juice
- 3 cup vegetable stock
- 2 tablespoon butter
- 1 teaspoon baking soda
- sea salt(optional)
- Parmesan cheese, grated, for serving(optional)
Instructions
- 1
Saute onion in olive oil over medium heat until browned.
- 2
Add garlic and saute.
- 3
Dice whole canned tomatoes.
- 4
Add diced tomatoes with juices, stock, basil and butter to pot. Stir until butter melts.
- 5
Add baking soda. Stir as soup fizzes.
- 6
Bring to boil, then simmer.
- 7
Optional: blend part or all for smoother texture.
- 8
Serve with grated Parmesan.
Tips
Baking soda fizz looks dramatic but subsides within seconds of stirring. Use a pot with 5+ quart capacity to contain the momentary bubble-up.
Fresh basil adds brightness; dried works but use 1.5 teaspoons and add it with stock to bloom. Parmesan crust on top is essential to the flavor profile.
Good to Know
Refrigerate up to 4 days in airtight container. Freeze up to 3 months. Thaw in refrigerator before reheating gently over low heat.
Make full recipe 1 day ahead. Baking soda reaction is immediate; do not pre-add. Stir and reheat gently before serving.
Ladle hot into bowls. Top generously with grated Parmesan. Pair with crusty bread or grilled cheese for a full meal.
Common Mistakes
Use a pot large enough for fizz to prevent overflow when baking soda activates.
Do not skip the onion browning step (10-12 min); it builds the soup's savory foundation.
Avoid high heat during simmering; gentle bubble maintains texture.
Substitutions
Dairy-Free Swaps
General Alternatives
FAQ
Can I use fresh tomatoes instead of canned?
Yes. Use 3 pounds fresh tomatoes, blanched and diced. Simmer 10-15 minutes longer to concentrate flavor. Canned tomatoes are more convenient and deliver consistent acidity for the baking soda reaction.
What if I don't have baking soda?
Omit it. The soup is still good but will taste tangier. Baking soda neutralizes canned tomato acidity and adds subtle creaminess without dairy. A pinch of sugar (1/2 teaspoon) can offset acidity instead.
How long can I store this and can I freeze it?
Refrigerate up to 4 days in airtight container. Freeze up to 3 months in freezer bags or containers. Thaw overnight in fridge and reheat gently over low heat to preserve texture.