Vegetable Soup

Ingredients

• 7 oz carrot
• 10 oz parsnip
• 10 oz potato
• 1.25 oz butter
• 5 tsp flour
• 1 tsp made mustard
• to taste salt
• to taste pepper
• 2 egg yolks
• 2.25 quarts water

Method

Cut the carrot, parsnip, and potato into thin, even slices — uniform thickness matters because these roots cook at different rates and you want all three tender at the same moment. Parsnip softens fastest, potato slowest; slicing thin compresses that window.

Bring the water to a rolling boil in a heavy-bottomed pot, then add the vegetables. Maintain a steady boil — not a timid simmer — for two and a half hours. The vigorous movement keeps the vegetables from clumping and helps break down their cell walls into the liquid. Top up the water as it reduces, keeping roughly two quarts in the pot. You're building a soup base where the vegetable solids soften into a soft mass and the broth becomes milky-sweet from released starches and sugars.

Make a liaison while the vegetables cook. Cream the butter with the flour, mustard, salt, and pepper until you've got a smooth paste — this is a one-pot-cooking roux, not a traditional white sauce. Slacken it with cold water (roughly one-quarter pint) and stir it in thoroughly so no lumps form. Stir this directly into the boiling soup and cook for ten minutes. The flour thickens through starch gelatinisation; the mustard sharpens the dulled sweetness of overcooked root vegetables and cuts any mealy flavour from the potato.

Crack the egg yolks into your serving tureen and whisk them lightly. Pour the hot soup directly over them whilst stirring constantly — the heat denatures the proteins and creates a silky, rich finish through emulsification. This is your emulsion step: the yolks bind fat and liquid into a cohesive whole rather than letting them split. The soup should coat a spoon lightly when it's done. Taste and adjust salt and pepper. Serve at once.