2/3 cup all-purpose flour
1 teaspoon salt
1/2 teaspoon dry mustard
Dash of cayenne
3 cup milk
3/4 teaspoon Worcestershire sauce
1/3 cup butter
3 cups grated sharp Cheddar cheese
Combine flour, salt, dry mustard and cayenne. Add 1 cup milk gradually to form a paste. Mix in remainder of milk and Worcestershire sauce. Melt butter in a double boiler. Add milk mixture. Cook and stir over hot water until thickened. Add cheese and stir until melted. Lay tomatoes slices on top of toast. Spoon rarebit over toast and tomato slices.
Beer Rarebit: Omit milk, and use ale or beer instead.