Form the ground beef into wide flat thin patties. Season with salt and pepper and set aside.
If using, preheat a large skillet.
In a large skillet over medium heat, saute the onions and peppers with a pinch of salt, over medium heat until soft, about 5 to 7 minutes. Remove from pan, set aside.
Salt the patties. Swirl 1 tbs butter in the pan to coat. Add the patties and cook 3 to 5 minutes, flipping once halfway through cook time. Remove from pan.
If using the skillet, wipe down.
Butter the outside of each slice of bread. Lay a slice of cheese on each piece of bread. Add a patty, top with onion and pepper mix, a slice of tomato, 2 slices of bacon, and another slice of cheese. Add the top piece of bread, butter side out.
Place sandwiches on pre-heated griddle or hot skillet. Cook until golden brown and cheese is melted through, flipping once as needed to brown both sides.