Combine the shredded cheese, flour, and mustard in a large plastic bag and shake to mix. Pour the milk in a large saucepan. Cook over medium heat until the milk begins to simmer. Gradually stir in the cheese mixture and worcestershire sauce. Continue to cook and stir until the cheese melts and the sauce is smooth. Toast the bread and cut each slice into quarters. Top each quartered piece of toast with half a tomato slice. Pour cheese sauce over tomato and toast, and sprinkle each piece with bacon crumbs.
Preparation Time: 25 minutes
Serves: 4-6 with 16 pieces