Guacamole with Garlic Confit from Rosewood San Miguel de Allende

Name: Guacamole with Garlic Confit from Rosewood San Miguel de Allende
Ingredients: 2 tablespoons finely chopped white onion; Pepper; 1 head of garlic, peeled; Olive oil; Salt; 4 ounces tomatoes finely chopped; 4 Serrano chiles, finely chopped; 3 heaping tablespoons roughly chopped cilantro; 3 large avocados (1 pound each); Lime juice; 1 heaping tablespoon finely chopped white onion; 2 heaping tablespoons roughly chopped cilantro; 1 tablespoon of the finely chopped Serrano chiles