Dice 2 medium shallots and mince 2 garlic cloves.
Melt 2 tablespoons unsalted butter in a 10-inch or larger skillet over medium heat. Add the shallot and garlic, and cook, stirring occasionally, until softened, about 3 minutes. Add 8 ounces sliced cremini mushrooms, 1 teaspoon dried thyme, and 1 teaspoon kosher salt, and cook, stirring occasionally until the mushrooms release their liquid, about 8 minutes.
Add ½ cup chicken or vegetable broth and scrape up any browned bits from the bottom of the pot with a wooden spoon. Cook until the broth is reduced by half, about 1 minute. Stir in 2 cups cooked rice and cook until heated through, about 2 minutes.
