4.

Using a thin spatula, transfer Mason jar lid to a paper towel–lined plate. Pour excess water out of the skillet and return it to the stovetop with the heat off. Flip Mason jar lid over and gently remove it to release egg. Place egg on top of bacon and top with cheese slice. Close sandwich, wrap in aluminum foil, and return to the now-empty skillet. Let it warm up in the skillet for 2 minutes with the heat off, flipping occasionally. Unwrap and serve immediately.