Name: To Ragoo a Liver, or Kidneys
Ingredients: 1 liver or kidneys, cut into thin slices; flour, for dusting; boiling water; parsley, chopped; young onions, chopped; ketchup, to taste; vinegar, to taste; coarse sea salt, to taste; fried parsley, for garnish

Why it works: Parsley and onion are a kitchen classic. They rank in the top 9% of all ingredient pairs, and cooks put them together in 25,843 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

To Ragoo a Liver, or Kidneys

Ingredients

Directions

The book gives no cooking times; the times in the steps were added in transcription, so check for doneness rather than trusting the clock.

Brown the liver or kidneys in a pan.
Remove from the pan and dust with flour.
Pour boiling water into the pan and add parsley and onions.
Bring to a boil and season with ketchup, vinegar, and salt.
Return the liver to the pan and let it boil for 2-3 minutes.
Garnish with fried parsley before serving.

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.

Parsley + oniontop 9% of all pairs

Smell alikemoderate

Cooked together25,843 recipes

Shared aroma: 2,4-decadienal (seaweed).
Flour + parsleytop 12% of all pairs

Smell alikemoderate

Cooked together16,675 recipes

Shared aroma: isobutyraldehyde (malty, green).
Flour + ketchuptop 13% of all pairs

Smell alikemoderate

Cooked together2,435 recipes

Shared aroma: ethanol (alcoholic, ethereal).
Onion + vinegartop 14% of all pairs

Smell alikemoderate

Cooked together18,226 recipes

Shared aroma: acetic acid (sour, vinegar).
Liver + oniontop 15% of all pairs

Smell alikelow

Cooked together1,420 recipes

Shared aroma: furaneol (caramel, strawberry).

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

What each ingredient does

Liver or kidneys: Forms the main meat of the ragout, browned first for flavour and then cooked gently in the sauce.
Flour: Dusting on the meat helps thicken the liquid and gives the pieces a light coating.
Young onions: Add sweetness and aroma as they simmer in the liquid.

The step that matters

Return the liver to the pan and let it boil for 2-3 minutes. Liver and kidney turn tough and grainy when overcooked. A short simmer in the sauce cooks them through while keeping them tender.

Swap the parsley

How well each one fits the dish's main ingredients (liver, flour, onion, ketchup, vinegar):

Capersfits better
Garlicfits better
Celeryfits about as well
Parsleythe original

Fit is the average pairing score against liver, flour, onion, ketchup, vinegar. 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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To Ragoo a Liver, or Kidneys