Name: Roe Sauce
Ingredients: soft roes of mackerel; 1 egg yolk; ¼ teaspoon salt; ¼ teaspoon pepper; 1 tablespoon fennel, scalded and chopped; 1 tablespoon parsley, scalded and chopped; 2 tablespoons melted butter; optional: 1 tablespoon catsup, essence of anchovy, or walnut pickle

Why it works: Fennel and parsley match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 625 recipes. Both carry myristicin, which smells spice, warm. The science ↓

Roe Sauce

Ingredients

soft roes of mackerel
1 egg yolk
¼ teaspoon salt
¼ teaspoon pepper
1 tablespoon fennel, scalded and chopped
1 tablespoon parsley, scalded and chopped
2 tablespoons melted butter
optional: 1 tablespoon catsup, essence of anchovy, or walnut pickle

Directions

Prepare the roe

Boil the soft roes of mackerel and remove all skin.
Bruise the roes with the back of a wooden spoon.

Make the sauce

In a bowl, beat the egg yolk with salt and pepper.
Add the chopped fennel and parsley to the egg mixture and rub together.
Stir the mixture into the melted butter.
Optionally, add catsup, essence of anchovy, or walnut pickle to taste.

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.

Fennel + parsleytop 1% of all pairs

Smell alikestrong

Cooked together625 recipes

Shared aroma: myristicin (spice, warm).
Pepper + parsleytop 2% of all pairs

Smell alikestrong

Cooked together34,122 recipes

Shared aroma: 4'-methylacetophenone (bitter almond).
Roe + anchovytop 6% of all pairs

Smell alikemoderate

Cooked together65 recipes

Shared aroma: 1-octen-3-ol (mushroom, earthy).
Pepper + fenneltop 7% of all pairs

Smell alikestrong

Cooked together1,216 recipes

Shared aroma: myristicin (spice, warm).
Egg + anchovytop 12% of all pairs

Smell alikemoderate

Cooked together2,330 recipes

Shared aroma: decanal (soap, orange peel).

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

What each ingredient does

Soft roes of mackerel: Provide the main body and rich flavour of the sauce.
Egg yolk: Binds the mixture and gives it a smooth, creamy texture.
Melted butter: Adds fat and moisture, giving the sauce a silky mouthfeel.

Swap the fennel

How well each one fits the dish's main ingredients (roe, egg, pepper, parsley, butter, anchovy):

Capersfits better
Thymefits better
Tarragonfits better
Fennelthe original

Fit is the average pairing score against roe, egg, pepper, parsley, butter, anchovy. 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.