This cheesy appetizer relies on just a few ingredients and can be put together in a snap.
Preheat oven to 425 degrees. Toss mushrooms with olive oil and salt on a rimmed baking sheet. Bake, tossing once, until golden, 20 to 25 minutes. Transfer mushrooms to a 6-inch ovenproof skillet. Top with Taleggio. Bake until bubbly, about 5 minutes. Top with fresh thyme. Serve with crostini.