Place English muffin in toaster and toast.
In a microwave safe bowl, about the same diameter as the English muffin, place the 1 slice Canadian bacon and 3 egg whites. Season with salt and pepper. Loosely cover with plastic wrap. Microwave on high for 1 minute. Remove from microwave and gently stir egg whites. Microwave 30 seconds more. Remove and immediately place a cheese slice over hot egg whites. Slide onto toasted English muffin. Repeat with remaining ingredients.