Preheat the oven to 400 degrees F.
Score the outside edges of the bologna with a knife, to prevent the meat from curling up when heating. Place the bologna in a cast iron skillet or hot grill and cook just until the bologna is charred or fried slightly to bring out the flavor. Remove from the heat.
Remove the top bun and cut about a 2-inch square out of the bun. Discard the cut portion.
Place 1 slice of cheese on the bottom bun and replace the top bun. Stuff the bologna in the cut- out hole. Grate about 1 to 2 tablespoons of pepper jack cheese on top of each slice of bologna.
Stuff each hole with about 2 to 3 tablespoons of mashed potatoes or macaroni and cheese.
Sprinkle the tops with green onion and bacon bits.
Place the boats on a baking sheet and bake for about 5 to 10 minutes, or until the buns are lightly toasted and the ingredients warmed through.