Split the English muffins and toast them in the toaster until golden, about 2 to 3 minutes.
Heat a large non-stick skillet over medium-low heat and coat with cooking spray. Spray two egg rings or wide mason jar lids if you have them.
Pour the egg whites into the rings, or as two flat rounds, and cook for about 3 minutes, covering the pan for the last minute, until fully set. Fold any edges in to fit the muffins.
Move the eggs aside, add the peameal bacon slices and cook over medium heat for about 2 minutes per side, until browned and 71°C (160°F) inside.
Lay the cheddar on the egg rounds to soften for 30 seconds.
Stack each muffin with spinach, peameal bacon and a cheesy egg round, and close with the top.