Add the fat to a large stainless steel, or cast-iron frying pan over high heat until it begins to smoke lightly. Place in the mushrooms, season with salt, and cook for 2 minutes without touching them.
Sauté the mushrooms for 6-8 minutes or until they are well browned. Scoot the mushrooms to 1 side of the pan, and in the other, the shallots, garlic, and 1 tablespoon of butter.
Remove the pan from the heat and deglaze with the brandy. Return the pan to the cooktop and cook for 30 to 45 seconds or until all the alcohol has been absorbed into the mushrooms.