PREP

Peel the pearl onions, place in a small pot, and cover with cold water. Add 1 tablespoon (14 g) of the butter and bring the water to a boil over high heat. Let it boil until the water evaporates (do not allow the onions to take on any color), then remove from the heat and set aside.

In the second small pot, repeat the procedure with the mushrooms, cooking them in water and 1 tablespoon (14 g) of the butter just until they are tender. Set aside.

COOK THE VEAL

Place the veal in the large pot. Cover with water and add the bouquet garni, onion, carrot, and celery. Bring the mixture to a boil, then reduce to a simmer. Let cook over low heat for 2 hours, periodically skimming away and discarding meat scum, until the veal is fork-tender (meaning it can be easily cut with the side of a fork). Do not undercook. Do not overcook to mush! Strain the meat and set it aside. Strain the broth and keep it hot over heat. Discard the bouquet garni and the vegetables.

THE SAUCE

In the medium pot, melt the remaining 4 tablespoons (56 g) of butter over medium heat, and once it has foamed and subsided, whisk in the flour, making sure it is completely incorporated. Cook over medium-low heat, stirring frequently. Do not color the flour. (What you are doing, by the way–in case you didn’t know–is making a roux.) Gradually add 1 cup (450 ml) of the hot broth, whisking constantly to incorporate smoothly. Add the remaining broth and bring to a boil, cooking and stirring until the mixture begins to thicken. Add the veal, pearl onions, mushrooms, and cream. Stir. Bring to a boil, reduce to a simmer, and heat for 5 to 8 minutes. Season with salt and white pepper.

FINISH

Just before serving, place the egg yolk in the small bowl and add about a ¼ cup (112 ml) of the hot sauce from the stew. Whisk well and add this mixture to the pot. Stir. Do not allow the sauce to come to a boil! Add the lemon juice, season again as needed, and serve with absolutely white rice.