Preheat oven to 400 degrees Fahrenheit and place goat cheese in the center of a shallow baking dish or small parchment lined baking sheet.
Toss tomatoes with balsamic and add to one side of the baking dish, placing chopped mushrooms on the other. Reserve one garlic clove and scatter the remainder around skillet.
Drizzle evenly with olive oil and sprinkle with salt and a few cracks of crushed black pepper then bake in preheated oven until garlic is soft, cheese is browned and tomatoes are bursting, 25-35 minutes.
Meanwhile make bruschetta. Slice loaf about ½ inch thick, rub with remaining garlic clove, drizzle with remaining 2 tablespoons olive oil and sprinkle with salt. Cut slices on the bias to make toast points and add to the oven during the last five minutes of baking either directly on the rack or on a baking sheet. Bake until golden and crisp flipping once if using a baking sheet.