In a saucepan over medium heat, melt butter and slowly whisk in flour until combined and forms a thick paste (roux). Cook for 3-4 minutes without color.
Whisk half & half into the roux and cook over medium heat until the cream begins to simmer, about 2-3 minutes.
Remove sauce from heat and slowly whisk in cheeses until the Mornay sauce is smooth. Add nutmeg, cayenne and salt to taste.
Using a bread knife, cut entire sheet of rolls through the middle keeping the tops intact and bottoms intact. Brush cut sides each with 1 T of melted butter. Brush the bottom of a 2” deep gratin dish or pan with butter. Then place bottom half of the in dish ensuring that it fits snug but a little space between the sides of the pan.
Slice smoked turkey up into strips. Spread evenly over the layer of bread then top with 12 slices of tomato lining them up so each slice sits on one bun.
Drizzle the Mornay sauce over the top evenly “coast to coast!”.
Place the top portion of the roll tops on top - lining up with the bottoms.
Place the entire dish in a 350 degree F pre-heated oven and bake for 10 minutes.
After 10 minutes, brush top with remaining 1 T melted butter. Sprinkle with grated parmesan and bacon.
Cook for a further 3-4 minutes until golden brown on top and cheese is bubbly around edges.