Preheat oven to 375 degrees F.
Combine the mushrooms and garlic in a large roasting pan, add the olive oil, and pepper and stir to combine. Add the sprigs of thyme and roast in the oven until golden brown and all of the liquid has evaporated, 25 to 30 minutes, stirring occasionally. Remove from the oven and stir in the Worcestershire, salt, and chopped thyme.
