Preheat the oven to 350 degrees.
Heat a large cast-iron pan over medium heat. Mix together the mashed cranberry sauce and Dijon mustard until fully incorporated. Sauté the Brussels sprout leaves in butter with a pinch of salt and black pepper for 2 minutes.
Lay out the bread and add a thin layer of the cranberry mustard to each slice of bread. Add and form a thin layer of the stuffing on the bottom piece of bread. Add the sliced turkey breast and some pulled leg meat on top of the stuffing. Add the leftover pumpkin or squash to the Brussels sprout leaves and distribute the Brussels sprout leaves and pumpkin over the turkey.
Place the other piece of bread on top and brush both top pieces of bread with softened butter. Add some butter to the warmed cast-iron pan and place the unbuttered side in the pan. Place in the oven after 2 minutes on the stove. Very carefully, flip the sandwich after 4 minutes and add a thin layer of mashed potatoes across the top.
Put the pan back in the oven for 4 more minutes, then turn to broil and lightly brown the potatoes (careful not to burn). Put the sandwich on a plate and fry up the eggs over easy in butter and add over the sandwich. Pour hot turkey gravy over the top and serve immediately. Take a nap.