Preheat the broiler to high heat.
Place mushrooms, rounded side up, in a large, oven proof sauté pan that will fit under the broiler.
Brush mushroom tops liberally with clarified butter.
Place pan under hot broiler and cook until mushrooms are golden brown. Remove from oven.
Place pan on stove top over high heat.
Add lemon juice and white wine. Simmer for 6 minutes, until the liquid has reduced by half.
Add chicken stock. Continue to simmer until the liquid has again reduced by half, about 4 minutes.
Add salt and butter. Shake and swirl pan vigorously to emulsify the sauce.
Using tongs, transfer the mushrooms to individual plates or a serving platter.
Drizzle with the cooking sauce.
Serve hot.