This is perhaps the most popular avocado sauce used by taco truck vendors in Mexico. A little sour and very creamy, it???s used to top everything from totopos (fried tortilla chips) to tacos and chilaquiles. The acidity of the tomatillos keeps the avocado fresh and vibrantly green for up to three days, if properly refrigerated. You can put it in a squirt bottle or spoon it directly onto your food. This recipe has a spicy kick, so if you desire a milder flavor, seed and devein the chiles. My daughter Nikki, who doesn???t care much for avocados, eats this sauce by the spoonful. Try saying the name of this sauce quickly and you???ll see how catchy it is.