Make cheese taco shells by heating a large skillet over low-medium heat. Place ¼ cup measurements of cheese in small mounds onto the skillet. Let melt and cook until the bottoms and edges are golden brown. Remove and let cool slightly. When they are cool enough to handle with your hands, shape them into a taco shell. Set aside and let cool completely.
Turn the heat down to low and add 1 tablespoon of butter onto the pan. Pour in eggs and slowly cook, stirring every 30 seconds until light and fluffy. Turn off heat.
Build breakfast tacos by adding eggs, avocado, salsa, and bacon to cheese shells. Garnish with green onion or cilantro if desired.