Name: Rusk, or Zwieback
Ingredients: ½ cup scalded milk; ¼ cup sugar; 2 cakes yeast; 3 eggs; ½ cup melted butter; Flour (enough to handle); ½ teaspoon salt

Why it works: Milk and butter are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 81,283 recipes. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓

Rusk, or Zwieback

Oven, in the book's wordsA moderate oven

Ingredients

Directions

The book says “a moderate oven”. The 350°F in the steps is the modern equivalent, not the book's own figure.

Make the sponge

Cool the milk and add the yeast.
Stir in 1 tablespoon sugar and 1 cup of flour; beat well.
Let the mixture rise until very light.

Make the dough

Add the remaining sugar, melted butter, and unbeaten eggs one at a time.
Add enough flour to handle the dough.
Let it rise until double in bulk.

Bake and serve

Bake in a moderate oven (350°F / 175°C) for about 20 minutes.
When cool, cut into slices, toast, and serve.

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.

Milk + buttertop 7% of all pairs

Smell alikemoderate

Cooked together81,283 recipes

Shared aroma: (z)-4-heptenal (biscuit, cream).
Butter + flourtop 12% of all pairs

Smell alikelow

Cooked together124,287 recipes

Shared aroma: isobutyraldehyde (malty, green).
Milk + flourtop 14% of all pairs

Smell alikelow

Cooked together78,219 recipes

Shared aroma: isobutyraldehyde (malty, green).
Sugar + flourtop 15% of all pairs

Smell alikemoderate

Cooked together92,116 recipes

Shared aroma: phenylacetaldehyde (hawthorne, honey).
Egg + flourtop 15% of all pairs

Smell alikelow

Cooked together106,462 recipes

Shared aroma: isobutyraldehyde (malty, green).

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

Yeast: Ferments the dough, producing gas that makes it rise and become light.
Eggs: Add structure and richness to the dough as it sets in the oven.
Butter: Adds fat for a tender texture and rich flavour.
Flour: Forms the gluten network that gives the dough its structure.
Sugar: Feeds the yeast and adds sweetness and browning.

“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.