Name: Chocolate Filling No. 1
Ingredients: 1 cup powdered sugar; 2 egg yolks; ½ cup boiling water; 4 ounces sweet vanilla chocolate

Why it works: Vanilla and chocolate are a kitchen classic. They rank in the top 5% of all ingredient pairs, and cooks put them together in 10,020 recipes. Both carry sotolon, which smells curry, maple. The science ↓

Chocolate Filling No. 1

Ingredients

1 cup powdered sugar
2 egg yolks
½ cup boiling water
4 ounces sweet vanilla chocolate

Directions

Make the filling

In a bowl, combine powdered sugar, egg yolks, and boiling water.
Add the sweet vanilla chocolate that has been melted over a warm place.
Stir until the mixture is smooth and creamy.

Assemble

Spread the filling between layers of cake.

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.

Vanilla + chocolatetop 5% of all pairs

Smell alikemoderate

Cooked together10,020 recipes

Shared aroma: sotolon (curry, maple).
Sugar + vanillatop 8% of all pairs

Smell alikelow

Cooked together35,032 recipes

Shared aroma: beta-damascenone (apple, rose).
Sugar + chocolatetop 13% of all pairs

Smell alikemoderate

Cooked together15,404 recipes

Shared aroma: guaiacol (smoky, sweet).
Sugar + eggtop 21% of all pairs

Smell alikemoderate

Cooked together122,807 recipes

Shared aroma: 2-nonenal (fatty, green).
Egg + vanillatop 23% of all pairs

Smell alikelow

Cooked together27,347 recipes

Shared aroma: 1-octen-3-ol (mushroom, earthy).

Sugar and vanilla barely smell alike, yet cooks put them together in 35,032 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: Add richness and help thicken the filling as it sets.
Powdered sugar: Adds sweetness and dissolves easily for a smooth texture.
Sweet vanilla chocolate: Gives the filling its main flavor and body as it firms.

“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.