1Preheat a skillet over medium heat.
Cook the bacon in the skillet until crispy, about 5-7 minutes. Remove and drain on paper towels.
In the same skillet, add the butter and let it melt.
Slice the onion thinly and add to the skillet. Cook until softened and slightly caramelized, about 5 minutes.
Crack the eggs into the skillet and cook to your desired doneness. Season with salt and pepper.
Toast the bread slices in a toaster or in the skillet until golden brown.
Assemble the sandwich by placing a slice of cheese on a piece of toast, followed by the cooked bacon, caramelized onions, and a cooked egg. Top with another slice of toast.
Repeat for the remaining sandwiches.
Serve immediately and enjoy your Bacon and Egg Breakfast Sandwich!