Name: Kidney Toasts
Ingredients: 1 kidney; surrounding fat; pepper; coarse sea salt; grated lemon peel; nutmeg; 1 egg yolk; thinly sliced toasted bread; butter

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 ↓

Kidney Toasts

Ingredients

Directions

The book gives no oven temperature. The 400°F (200°C) in the steps was added when the recipe was transcribed, as a starting point.

Prepare the filling

Pound the kidney and surrounding fat in a mortar.
Season with pepper, coarse sea salt, grated lemon peel, and nutmeg.
Mix in the beaten egg yolk.
Spread the mixture on thinly sliced toasted bread cut into squares.

Bake and serve

Melt a little butter in a dish and add the kidney toasts.
Brown the toasts in a 400°F (200°C) oven.
Serve very hot.

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.

Pepper + lemontop 3% of all pairs

Smell alikestrong

Cooked together27,047 recipes

Shared aroma: trans-2-nonenal (cardboard, fatty).
Lemon + nutmegtop 5% of all pairs

Smell alikestrong

Cooked together11,318 recipes

Shared aroma: beta-phellandrene (minty, terpene).
Bread + buttertop 7% of all pairs

Smell alikemoderate

Cooked together27,232 recipes

Shared aroma: delta-decalactone (sweet, creamy).
Pepper + nutmegtop 7% of all pairs

Smell alikestrong

Cooked together13,015 recipes

Shared aroma: 4'-methylacetophenone (bitter almond).
Egg + breadtop 13% of all pairs

Smell alikemoderate

Cooked together22,662 recipes

Shared aroma: (e)-2-octenal (fatty, green).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Kidney: Provides the main savory meaty base that gives the spread its body and flavor.
Egg yolk: Binds the pounded mixture together so it spreads evenly on the bread.
Butter: Adds fat that helps the toasts brown and gives a rich flavor.
Toasted bread: Forms the crisp base that holds the spread and carries it to the table.

The step that matters

Brown the toasts in a 400°F (200°C) oven. Browning depends on surface heat and fat; if the toasts are not hot enough or are left too long, the bread can dry out or scorch before the spread is heated through. Serve them while still hot, since the crisp texture fades as they cool.

“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.