Why it works: Pepper and lemon match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 27,047 recipes. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓
A Gravy Without Meat
Ingredients
Directions
Prepare
Slice the onion and flour it.
Fry the onion in butter until brown.
Make the gravy
In a basin, combine small beer, water, pepper, salt, lemon peel, bruised cloves, and walnut pickle or mushroom ketchup.
Add the fried onion to the mixture and simmer covered for 20 minutes.
Strain the gravy for use.
Let it cool, then remove the fat.
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.
Photo for illustrative purposes only · Contact us to use it
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.
-
Pepper + lemontop 3% of all pairsSmell alikestrongCooked together27,047 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
-
Pepper + clovetop 5% of all pairsSmell alikestrongCooked together17,451 recipes
Shared aroma: ethyl octanoate (fruity, wine).
-
Clove + walnuttop 9% of all pairsSmell alikestrongCooked together1,592 recipes
Shared aroma: eucalyptol (eucalyptus, herbal).
-
Lemon + clovetop 10% of all pairsSmell alikestrongCooked together8,150 recipes
Shared aroma: eucalyptol (eucalyptus, herbal).
-
Lemon + walnuttop 10% of all pairsSmell alikestrongCooked together2,149 recipes
Shared aroma: 2-nonenal (fatty, green).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Onion
- Frying it brown adds sweetness and deep savoury flavour through browning.
- Butter
- Fat for frying the onion, carrying flavour and helping it brown.
- Small beer
- Liquid base that adds malty, slightly bitter flavour to the gravy.
- Walnut pickle or mushroom ketchup
- Concentrated savoury seasoning that adds depth and umami to the gravy.
- Lemon peel
- Adds bright aromatic oils that lift the savoury flavours.
The step that matters
Frying the onion until brown. Browning the onion in butter develops its sweetness and deep flavour through the Maillard reaction. Pale onion gives a flat, washed-out gravy, and burnt onion turns it bitter.
Swap the onion
How well each one fits the dish's main ingredients (beer, pepper, lemon, clove, walnut, butter):
- Capsicumfits better
- Shallotfits better
- Lettucefits better
- Onionthe original
Fit is the average pairing score against beer, pepper, lemon, clove, walnut, butter. Candidates are from the same food group and used in at least 100 recipes.
“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.
You might also like
The free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.
Prefer an account? Create a free account to save pairings and unlock the full chemistry.

Lemon Sauce236 recipes
Tomato Soup526 recipes
Brown Bread461 recipes
Mutton Broth292 recipes