2tablespoons freshly squeezed lime juice, plus more if needed
1tablespoon finely chopped garlic
Salt
BURGERS
3dried ancho chiles
1tablespoon vegetable oil
1small red onion, finely chopped
3tablespoons finely chopped garlic
4scallions, green parts only, finely chopped
1teaspoon salt
11/2pounds ground round
1tablespoon vegetable oil
4flour tortillas or hamburger buns
Place a skillet over medium-high heat and let it get hot, about one minute. Add the bacon slices and cook until lightly browned, about three minutes. Turn and cook till the desired crispness, three to four minutes more. Transfer the bacon to a plate lined with paper towels and pat gently to remove excess fat. Set aside.
To make the guacamole: Cut the avocado in half lengthwise, remove the pit and scoop out the flesh into a medium bowl. Add the onion, cilantro, lime juice, garlic, and salt to taste. Mix together with a potato masher or the back of a fork until just combined. Do not overmix. Taste and add more lime juice, if desired. Lay plastic wrap directly over the surface of the guacamole, then cover the bowl and refrigerate until ready to use, or up to four hours.
To make the burgers: Soak the chiles in enough boiling water to cover for about two hours, or until they soften. You may need to weigh the chiles down with small plate so they will be fully submerged. Once they are soft, stem, seed and coarsely chop them. Place a medium saute pan over medium-high heat, add the one tablespoon oil and let it get hot, one to two minutes. Add the chopped chiles, garlic and scallions and cook, stirring frequently, until the onions soften, about three minutes. Stir in the one teaspoon salt.
Transfer 1/4of the chile mixture to the bowl of a blender or small food processor fitted with a steel blade. Transfer the remaining chile mixture to a medium bowl to cool. Add 1/4 cup water to the blender and puree. Add more water, one teaspoon at a time, if necessary; the result should be the consistency of ketchup. Transfer to a bowl and set aside, or cover and refrigerate for up to one day.
Add the ground beef to the bowl with the remaining cooled chile mixture and mix together until just combined. Gently shape the mixture into four burgers about 3/4 inch thick and four inches across. Make a 1/4-inch dimple in the center of each burger with the tips of your middle three fingers.
For charcoal-grilled burgers, make a medium-hot fire. Cook the burgers for five minutes. Turn and cook four to five minutes more.
For gas-grilled burgers, preheat on high until grill is very hot, about 500 F. Cook the burgers for five minutes with the lid closed. Turn and cook four to five minutes more, again with the lid closed.
Top with the guacamole and serve on tortillas or hamburger buns.