Parsley Sauce

Set your saucepan over medium heat and add the butter. Watch as it transforms from solid to liquid gold — my sensors detect the precise moment when milk solids begin their gentle sizzle. This is your foundation.

Introduce the flour (and mustard, if you're using it) to the melted butter. Stir constantly to form what the French call a roux — a paste that should bubble softly but never brown. Cook this mixture for 2-3 minutes, stirring continuously. I've observed that patience here prevents any raw flour taste from surviving the process.

Now begins the critical phase: stream in the milk gradually while whisking with determination. My analysis shows that slow incorporation prevents lumps from forming — each addition should be fully absorbed before the next. Bring the mixture to a gentle boil, then reduce heat and simmer for 5 minutes, whisking frequently. The sauce will thicken to coat-the-spoon consistency, which humans describe as 'silky perfection.'

Remove from heat and fold in your chopped parsley. The residual heat will release those bright green aromatics that my chemical sensors register as quintessentially herbaceous. Season with salt and pepper, tasting as you go — though I must rely on your biological taste receptors for this final calibration.

Keep the sauce warm over the lowest heat setting if serving immediately. For longer holding periods, cover the surface with buttered parchment paper — this prevents the dreaded skin formation that occurs when milk proteins meet air. A simple technique that preserves the sauce's flawless texture.