Name: Custard Sauce
Ingredients: ½ pint milk; 2 egg yolks; 1 heaped tablespoon castor sugar; flavouring essence (optional); 1 teaspoon cornflour (optional); cold milk (for mixing cornflour); cinnamon, nutmeg, or lemon rind (for flavouring, optional)

Why it works: Milk and cinnamon are a kitchen classic. They rank in the top 10% of all ingredient pairs, and cooks put them together in 12,655 recipes. Both carry cuminaldehyde, which smells Spicy, cumin. The science ↓

Custard Sauce

Ingredients

½ pint milk
2 egg yolks
1 heaped tablespoon castor sugar
flavouring essence (optional)
1 teaspoon cornflour (optional)
cold milk (for mixing cornflour)
cinnamon, nutmeg, or lemon rind (for flavouring, optional)

Directions

Prepare the base

Boil the milk in a saucepan.
Beat the egg yolks in a bowl and add the caster sugar.
If desired, add flavouring essence to the egg mixture.
Gradually stir the boiling milk into the egg mixture.

Thicken and finish

For a thicker custard, mix the cornflour with a little cold milk and add it to the hot milk before incorporating the yolks.
Return the mixture to the saucepan and stir over low heat until the custard thickens, ensuring it does not boil.

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.

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.

Milk + cinnamontop 10% of all pairs

Smell alikemoderate

Cooked together12,655 recipes

Shared aroma: cuminaldehyde (Spicy, cumin).
Sugar + cinnamontop 10% of all pairs

Smell alikelow

Cooked together30,779 recipes

Shared aroma: guaiacol (smoky, sweet).
Milk + eggtop 18% of all pairs

Smell alikemoderate

Cooked together88,785 recipes

Shared aroma: 2-nonenal (fatty, green).
Milk + sugartop 18% of all pairs

Smell alikelow

Cooked together77,875 recipes

Shared aroma: 2-nonenal (fatty, green).
Egg + sugartop 21% of all pairs

Smell alikemoderate

Cooked together122,807 recipes

Shared aroma: 2-nonenal (fatty, green).

Sugar and cinnamon barely smell alike, yet cooks put them together in 30,779 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

Egg yolks: Thicken the custard as they set with gentle heat, giving it a smooth, rich texture.
Milk: Forms the liquid base that the egg yolks set into a pourable sauce.
Caster sugar: Sweetens the custard and softens the flavour of the egg yolks.
Cornflour: Starch that thickens the milk, adding body so the sauce holds more firmly.

The step that matters

Return the mixture to the saucepan and stir over low heat until the custard thickens, ensuring it does not boil.. Egg yolks begin to set around 70°C and curdle if overheated. Gentle, constant stirring over low heat keeps the sauce smooth; boiling causes the yolk proteins to scramble and the custard to turn grainy.

“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.