Turn oven to high Broil.

Make the meatloaf sauce by mixing together the sauce ingredients.

Butter both insides of the bread roll and place in oven to toast. Remove from oven when edges begin to get golden and then spread a generous layer of meatloaf sauce over the bottom half of bread. Top with a slice of meatloaf and a slice of cheese. Return to oven until cheese is melted.

Add a handful of spinach and place the top layer of bread. Serve with extra sauce for dipping, if desired.