Cream of Mushroom Soup

Method

1. saute14 min
   medium-high, single layer, undisturbed at first
   mushrooms + 2 tbsp butter in a wide pot — they will flood the pan with their own water within three minutes; keep the heat up and do not stir until that liquid has boiled off, because browning cannot start while the surface is wet. Only after the pan goes dry and quiet do they take color, and that color is the entire flavor of the soup
2. saute3 min
   medium, heat lowered
   + shallots + garlic + thyme + remaining butter, just until the shallots go translucent — garlic scorches in a dry browned pan in under a minute and turns the whole pot bitter
3. mix2 min
   medium, stirring constantly
   + flour, coating the mushrooms into a dry paste. Cook it the full two minutes: raw starch granules taste chalky and refuse to swell evenly later, which is what makes a lumpy cream soup lumpy
4. deglaze1 min
   medium-high
   + sherry, scraping the fond off the bottom — the browned film is water-soluble and belongs in the liquid, not welded to the pot
5. simmer18 min
   bare simmer, partly covered
   + chicken stock added in three additions with a whisk between each + bay leaf + porcini if using. Adding stock gradually lets the roux hydrate in stages instead of clumping around dry flour. Twenty minutes is what turns floury broth into something that coats a spoon
6. mash3 min
   off heat
   remove the bay leaf, then blend about three-quarters of the pot with an immersion blender and leave the rest in pieces — the purée is the body, the pieces are the proof it was made from mushrooms
7. temper3 min
   low, never boiling
   + heavy cream + salt + black pepper (+ nutmeg, lemon). Hold it below a simmer: boiling cream in an acidic, sherry-spiked pot breaks the fat out into greasy specks, and once it splits no amount of whisking brings it back = soup