Name: Kidney Toast
Ingredients: 4 sheep's kidneys; 1 ounce butter; ½ ounce flour; ½ cup stock from kidneys; 1 tablespoon cream; pepper to taste; coarse sea salt to taste; 1 teaspoon mushroom ketchup; buttered toast

Why it works: Butter and mushroom are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 12,525 recipes. Both carry trans-2-decenal, which smells waxy, orange. The science ↓

Kidney Toast

Ingredients

Directions

Make the sauce

Melt the butter in a saucepan and stir in the flour.
Gradually add the stock and bring the mixture to a boil.
Add the cream, the mushroom ketchup and the seasoning.

Finish and serve

Add the chopped kidneys.
Serve hot on buttered toast.

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.

Butter + mushroomtop 7% of all pairs

Smell alikemoderate

Cooked together12,525 recipes

Shared aroma: trans-2-decenal (waxy, orange).
Butter + creamtop 8% of all pairs

Smell alikemoderate

Cooked together41,516 recipes

Shared aroma: delta-dodecalactone (sweet, creamy).
Pepper + mushroomtop 11% of all pairs

Smell alikemoderate

Cooked together13,580 recipes

Shared aroma: 2-nonenal (fatty, green).
Butter + flourtop 12% of all pairs

Smell alikelow

Cooked together124,287 recipes

Shared aroma: isobutyraldehyde (malty, green).
Cream + ketchuptop 12% of all pairs

Smell alikemoderate

Cooked together279 recipes

Shared aroma: ethanol (alcoholic, ethereal).

Butter and flour barely smell alike, yet cooks put them together in 124,287 recipes: they work on texture and structure more than aroma.

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

What each ingredient does

Sheep's kidneys: Provide the main meat, which is cooked in the sauce and gives the dish its flavour.
Butter: Carries the flour and adds richness to the sauce.
Flour: Thickens the butter and stock into a smooth sauce.
Stock from kidneys: Forms the liquid base of the sauce, adding savoury depth.
Cream: Adds richness and a smoother, silkier texture to the sauce.

“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.