Preheat the oven to 350ºF.

Line a 9 by 13-inch rimmed baking sheet with parchment paper, leaving a 2-inch overhang on two sides.

Grease with nonstick spray.

Put the bacon on a separate baking sheet and bake until crispy, about 20 minutes.

In a large bowl, whisk together the eggs and season with salt and pepper.

Pour onto the prepared baking sheet.

Carefully transfer to the oven alongside the bacon and bake the eggs for 12 to 15 minutes until set.

Meanwhile, heat a large nonstick skillet over medium heat.

Add 1 tablespoon of the butter and begin toasting the bread on one side.

Transfer to a baking sheet and repeat with the remaining bread, adding 1 tablespoon of butter after every two slices.

Remove the eggs and bacon from the oven.

Reduce the oven temperature to 200ºF.

Drain the bacon on paper towels.

Invert the eggs onto a cutting board and discard the parchment paper.

Top the eggs with the cheese slices and cut into 6 squares.

Put an egg square on a piece of toasted bread.

Top with 2 slices of cooked bacon and sandwich with another piece of bread.

Repeat with the remaining ingredients until you have 6 sandwiches.

Place the egg sandwiches in the oven to keep warm until ready to serve.