Mushroom Duxelle

1 tablespoon unsalted butter or olive oil 2 tablespoons minced shallots 1/2 teaspoon minced garlic 10 ounces button mushrooms, finely chopped 1/4 teaspoon salt 1/8 teaspoon pepper

Heat the butter in a medium skillet over medium-high heat. Add the shallots and garlic and cook, stirring, for 30 seconds. Add the mushrooms, salt, and white pepper, reduce the heat to medium, and cook, stirring, until all the liquid has evaporated and the mushrooms begin to caramelize, about 12 minutes. Remove from the heat and let cool before using