Method for one serving: Heat 1/2 tablespoon of the butter in a saute pan over high heat. When butter is melted, add the onion to the pan and saute until lightly browned (carmelized). Set aside. Heat 1/2 tablespoon of the butter in a saute pan over medium heat. Place a corn tortilla in the pan and cook on both sides until lightly browned and crisp. Remove from pan and place on paper towel. Add 2 tablespoons of the olive oil to the saute pan and heat for a minute. Place 2 eggs in the pan and cook until over easy. Season the eggs with 1/4 teaspoon of salt and 1/4 teaspoon of black pepper. Put the eggs on top of the tortilla on a plate. Next, add the sausage to the pan and reheat it for 4 minutes. Place sausage on the eggs; sprinkle on top 1/3 cup of the cheese, 1/4 cup of the salsa, 2 tablespoons of the caramelized onion and 1 tablespoon of cilantro.