Use your favorite round country bread for these delicious open-face sandwiches. Cut slices of bread from the center of the loaf and make each about ¾-inch thick so that you'll have wonderfully generous sandwiches.
Preheat a grill on medium-high heat or preheat the broiler. Brush the squash with oil and season with the salt and pepper. Grill or broil, turning once or twice, until tender and nicely browned, 6-8 minutes. Set aside.
Grill or broil the bread until just lightly browned, about 1 minute per side. Rub the bread on both sides with the garlic and then discard the garlic.
Cover the tops of the slices with Brie, place on a cool part of the grill, and cover the grill (or broil) until the cheese is somewhat melted. Top with the grilled squash, tomato, and sprouts. Cut each sandwich in half and serve.