Name: Fried Tripe and Onions
Ingredients: Tripe, cut into slips (4 inches long, 3 inches wide); Batter for dipping; Boiling lard for frying; Onions, cut into 1-inch thick slices; Melted butter; Mustard; Vinegar (optional)

Why it works: Onion and mustard match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 9,259 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Fried Tripe and Onions

Ingredients

Directions

Dip the tripe slips in batter.
Fry the battered tripe in boiling lard until golden brown.
Fry the onion slices in the same manner until golden brown.
Serve the fried tripe on a plate with the fried onions underneath.
In a sauceboat, combine melted butter, a little mustard, and vinegar if desired.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.

Explore the science

The flavor team

The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.

Onion + mustardtop 6% of all pairs

Smell alikestrong

Cooked together9,259 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Mustard + vinegartop 7% of all pairs

Smell alikemoderate

Cooked together14,067 recipes

Shared aroma: isobutyraldehyde (malty, green).
Onion + vinegartop 14% of all pairs

Smell alikemoderate

Cooked together18,226 recipes

Shared aroma: acetic acid (sour, vinegar).
Onion + buttertop 15% of all pairs

Smell alikemoderate

Cooked together42,912 recipes

Shared aroma: decanal (soap, orange peel).
Butter + mustardtop 22% of all pairs

Smell alikemoderate

Cooked together8,003 recipes

Shared aroma: guaiacol (smoky, sweet).