The legendary open-faced Kentucky sandwich: thick Texas toast topped with roasted turkey, draped in a rich Mornay sauce, then broiled with tomato and crispy bacon.
Make the Mornay: Melt butter in a saucepan over medium heat. Whisk in flour and cook 2 minutes until golden and nutty. Gradually whisk in milk and cream. Cook 5-7 minutes, whisking constantly, until thick and smooth. Remove from heat, stir in both cheeses until melted. Season with salt, white pepper, and a pinch of nutmeg.
Preheat broiler: Set broiler to high. Arrange toasted bread in an oven-safe baking dish. (For traditional presentation, trim the crusts.)
Build: Place generous slices of turkey on each bread slice. Arrange tomato slices on top.
Sauce generously: Pour Mornay sauce over everything -- be generous, covering all the turkey completely.
Broil: Place under the broiler for 3-5 minutes until sauce is bubbly, lightly browned, and irresistible.
Finish: Remove from oven. Cross two strips of crispy bacon over each Hot Brown. Serve immediately -- this waits for no one.