Heat a nonstick pan to medium/high heat and add the bacon. Cook for about 3 minutes on one side then flip to continue cooking for another 2 minutes on the other side. Once browned and crispy, transfer bacon to a paper towel lined plate and allow to cool.
Pour out most of the bacon fat, leaving just a small amount to coat the bottom of the pan. Crack an egg and cook over medium/low heat for 3-4 minutes until the clear part turns white and the yolk is soft.
Toast the english muffin, add the slice of cheddar cheese to the toasted bread immediately after taking out of the toaster so the cheese can melt a bit. Add the bacon, cooked egg, and sliced avocado.