An open-faced sandwich of tomatoes, cheese, and homey bread.
Preheat broiler. Melt 2 tablespoons butter in a small saucepan over medium heat. Add shallot, and cook until tender, about 2 minutes. Add flour, and cook, stirring constantly, for 1 minute. Whisk in milk, and cook, stirring frequently, until thick, about 2 minutes. Remove from heat, and stir in 2 tablespoons cheese. Season with salt and pepper, and let cool slightly.
Spread remaining 3 tablespoons butter on bread, and top each slice with 2 tablespoons cheese sauce and 3 tomato slices. Season with salt and pepper. Divide remaining 1/2 cup cheese among sandwiches, and place under broiler. Cook until bubbling and golden brown, about 1 minute. Let cool slightly, season with pepper, and serve immediately.