Why it works: Potato and onion are a kitchen classic. They rank in the top 3% of all ingredient pairs, and cooks put them together in 9,023 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Shepherds Pie
Ingredients
Directions
The book says “a moderate oven”. The 350°F (175°C) in the steps is the modern equivalent, not the book's own figure.
Prepare
Preheat the oven to 350 °F (175 °C).
In a deep dish, combine the diced mutton, cold boiled potatoes, stock, salt, pepper, and butter.
Make the potato topping
In a pot, boil the peeled potatoes until tender, then mash them.
Mix in the cream, butter, salt, and pepper, beating until light.
Add enough flour to form a soft dough, about 1 cup.
Assemble and bake
Roll the dough into a thick sheet and cover the meat mixture with it.
Make a small hole in the center for steam to escape.
Bake for 1 hour and serve in the baking dish.
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.
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Potato + oniontop 3% of all pairsSmell alikemoderateCooked together9,023 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + creamtop 8% of all pairsSmell alikemoderateCooked together41,516 recipes
Shared aroma: delta-dodecalactone (sweet, creamy).
-
Pepper + potatotop 9% of all pairsSmell alikemoderateCooked together8,305 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Pepper + oniontop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 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
- Mutton
- Provides the savoury meat base that the dish is built around.
- Potatoes
- Form the moist filling and the mashed topping that gives the pie its body.
- Cream
- Adds richness and softness to the mashed potato, making it light and smooth.
- Butter
- Adds fat for richness and flavour in both the filling and the mashed topping.
- Flour
- Binds the mashed potato mixture into a soft dough that can be rolled into a sheet.
The step that matters
Making the dough sheet. Adding too much flour makes the dough tough and dense, while too little leaves it too soft to roll and cover the filling. Beating the mash until light also helps keep the topping tender.
Swap the onion
The recipe marks onion as optional. How well each one fits the dish's main ingredients (mutton, butter, pepper, potato, cream, flour):
- Leekfits about as well
- Spinachfits about as well
- Chivefits about as well
- Onionthe original
Fit is the average pairing score against mutton, butter, pepper, potato, cream, flour. 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.
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