The Egg McMuffin — that tasty and compact wedge of cheese, egg, and buttered toast — is only 300 calories. Plus, it's easy to make at home. So if you want to know how we get that egg and ham to be perfectly round, read on.
Pop the English muffin into a toaster and set it to the desired crispness level. Lay a ring mold (a round cookie cutter will work, too) over the bacon and trace a paring knife around its edge. The result should be a round slice of ham. Discard the rest.
Use a pastry brush to coat the inside of the ring with olive oil. Put the ring into a nonstick skillet and heat over medium-high heat. Lightly coat the skillet with olive oil using the pastry brush. Crack the egg into the ring; to break the yolk, use the edge of the cracked shell and tap.
Add a little water to the pan outside the ring and cover the pan with a lid. (This will create steam, which will help the egg cook well.) Cook until the whites have set and the water has nearly evaporated, about 1-1 ½ minutes.
Remove the egg from the pan, and remove the ring mold. (If it's a little hard to remove, simply use the paring knife to gently trace around the inside again.) Wipe out the pan. Put the Canadian bacon in the pan until warmed through, about 1 minute. Once the English muffin is toasted, lightly butter both halves. Layer on the cheese, egg, bacon, and the other half of the toast.