How to Make It
Light a charcoal grill or preheat the broiler and position a rack 6 inches from the heat. Using a spoon, scrape out the brown gills from the mushrooms. Set the mushrooms, top side up, on a large baking sheet and brush with 1/4 cup of the olive oil. Drizzle 1 tablespoon of the balsamic vinegar over the mushrooms and season with salt and pepper. Grill or broil for about 25 minutes, turning the mushrooms frequently, or until tender and browned. Transfer the mushrooms to a bowl and let cool.
Meanwhile, in a shallow bowl, toss the olives with the herbes de Provence and the remaining 1/4 cup of olive oil and 1/4 cup of balsamic vinegar. Add the mushrooms and turn to coat. Just before serving, sprinkle the goat cheese on top and season with salt and pepper.