Tomato + Onion
A proven pairing. Cooks put them together in 20,633 recipes, and they share 251 flavor molecules: the top 8% of all ingredient pairs.
Do tomato and onion go together?
Yes. 20,633 recipes in our collection combine them, and they share 251 flavor molecules. That places them in the top 8% of every ingredient pair we score.
Why they work
More than half of onion's flavor molecules (251 of 365) also occur in tomato. Among the shared key aromas are 2-isopropyl-3-methoxypyrazine (earthy, pea) and 2,4-decadienal (seaweed).
What each one brings
tomato
The fruit. Fruity notes make up 15% of its labelled aroma molecules, against 9% for onion. It carries 259 molecules onion doesn't have.
onion
The sulfurous side. Sulfurous notes make up 13% of its labelled aroma molecules, against 3% for tomato. It carries 114 molecules tomato doesn't have.
Add a third ingredient
- Garlic: the best fit for both, top 3% of pairs with tomato, top 1% with onion.
- Okra: top 3% of pairs with tomato, top 4% with onion.
- Avocado: top 2% of pairs with tomato, top 5% with onion.
- Olive: top 1% of pairs with tomato, top 8% with onion.
Ranked by the average of its two pairing scores. Only foods used in at least 100 recipes are suggested.
Recipes with tomato and onion
Almost always mains: 1,308 of the 1,627 recipes with a course label are mains (from a sample of 3,000 recipes that use both).
Can you swap one for the other?
Not really. Each has a lot the other lacks: tomato has 259 molecules onion doesn't, and onion has 114 that tomato doesn't. Treat them as partners, not stand-ins. This compares flavor only; texture, moisture and the job each does in a dish matter too.
All 251 shared molecules
See every shared molecule grouped by chemical class, with key aromas marked, plus the 259 only in tomato and the 114 only in onion.
Tomato and onion questions
Do tomato and onion go together?
A proven pairing. Cooks put them together in 20,633 recipes, and they share 251 flavor molecules: the top 8% of all ingredient pairs.
Why do tomato and onion taste good together?
More than half of onion's flavor molecules (251 of 365) also occur in tomato. Among the shared key aromas are 2-isopropyl-3-methoxypyrazine (earthy, pea) and 2,4-decadienal (seaweed).
What goes with tomato and onion?
Garlic is the best third ingredient: top 3% of pairs with tomato and top 1% with onion. Okra and avocado also fit both.
What can you make with tomato and onion?
Almost always mains: 1,308 of the 1,627 recipes with a course label are mains (from a sample of 3,000 recipes that use both). Common dishes include Cherry Tomatoes Sautéed with Green Onions, Cucumber, Tomato, and Onion Salad, Diabetic-Friendly Tomato Onion Soup, Fillets of Sole Provençale with Tomatoes, Onions and Cheese.
Can I use onion instead of tomato?
Not really. Each has a lot the other lacks: tomato has 259 molecules onion doesn't, and onion has 114 that tomato doesn't. Treat them as partners, not stand-ins. This compares flavor only; texture, moisture and the job each does in a dish matter too.
Compare other ingredients
Ranks compare this pair with 20,000 random ingredient pairs on CompKitchen. Molecule counts are what the studies and databases we aggregate have reported for each ingredient: a measure of coverage, not a full census. How we score pairs
Cite this analysis
Compound Kitchen (2026). Compound similarity analysis: Tomato vs Onion. https://compkitchen.com/compare/tomato-vs-onion. Accessed 2026-11-04.
@misc{compkitchen_compare_compound_similarity_analysis_tomato_vs_onion_2026,
title = {Compound similarity analysis: Tomato vs Onion},
author = {{Compound Kitchen}},
year = {2026},
url = {https://compkitchen.com/compare/tomato-vs-onion},
note = {Accessed: 2026-11-04}
}
Methodology DOI: 10.5281/zenodo.19719459 · CC BY 4.0 · Citations are a request, not a requirement.