Peel and mash the avocado with a dash of salt. Heat 2 T of the butter or ghee in a skillet over medium heat and, once the butter is melted and beginning to shimmer, gently crack the eggs into the hot pan. Sprinkle each of the eggs with a bit of salt and pepper and a small handful of gruyere. Add a teaspoon of water to the skillet and cover the pan with a lid. Allow to cook for about 4 minutes, then remove skillet from heat. Meanwhile, toast the English muffins and spread the remaining butter onto each half. Spread the avocado mash onto one side of each English muffin, top with a cheesy egg, then cap with the remaining half of the English muffin.