Preheat oven to 300 degrees Fahrenheit. Cut the large tomatoes into sixths, medium tomatoes in half, and leave the small tomatoes whole. Toss the tomatoes with the garlic, chèvre, olive oil, salt and pepper and place in a large cast iron pot or cocotte. Arrange the onion wedges in the pan in the olive oil. Place the pan in the oven and bake for 1 hour, then raise the heat to 350 degrees Fahrenheit and bake for 1 hour more.
To serve it as a main, toss it with the cooked pasta and 4 additional ounces of Vermont Creamery chevre and serve. To serve it as an appetizer, spread it on the toasted baguette slices.