Melt butter over medium-high heat. Add mushrooms and salt; cook and stir until well browned and caramelized, about 5 minutes. They will be wet and soggy at first but will dry out.
2
Add shallots and cook until they soften up and turn translucent, about 3 minutes. Add black pepper, cayenne, and white wine. Stir until wine evaporates, about 1 minute. Turn off the heat and transfer to a bowl to cool to room temperature.
3
Add pate to cooled mushroom mixture; toss and mash with a spoon until thoroughly combined. Set aside.
