1. Preheat the oven to 250°F.

2. Halve the tomatoes crosswise, and place them on a baking sheet. Drizzle them with 1 tablespoon of the olive oil and sprinkle with the sugar. Bake on the center rack of the oven for 3 hours. Using a spatula, carefully transfer the tomatoes to a plate to cool.

3. While the tomatoes are roasting, gently crumble the goat cheese into a bowl. Add 2 tablespoons of the olive oil, the orange zest, chopped basil, salt, and pepper. Cover and refrigerate until the tomatoes have finished roasting and are cooled.

4. When you are ready to serve the sandwiches, lightly toast the bread. Spread the cheese mixture on one side of each slice. Top with 2 whole basil leaves and 2 tomato halves. Sprinkle with salt and pepper, and drizzle with the remaining 1 tablespoon olive oil. Serve immediately.