1. Heat 1/4 cup of the oil in small skillet over medium heat. Add the garlic and chile peppers and cook, stirring frequently, until just brown, 1 to 2 minutes. Process with the cilantro, lime juice, 1/2 teaspoon of the salt, and black pepper in a blender or food processor until smooth.
2. Put the chicken in a shallow dish and spread half the garlic mixture over all sides of the chicken.
3. Heat 1 tablespoon of the oil in a large skillet over medium-high heat. Add the onion and cook, stirring occasionally, until golden but still slightly crunchy, about 5 minutes. Chop enough of the onion to make 1/4 cup and set aside. Put the rest of the onion on a plate. Save the skillet.
4. Peel and pit the avocados and put the flesh in a bowl. Add the reserved chopped onion, the remaining garlic mixture, and 1/4 teaspoon of the salt. Coarsely mash with a potato masher or fork.
5. Return the skillet to medium heat and add the remaining tablespoon oil. Lift each breast and let excess marinade drip off. Discard the extra marinade. Add the chicken to the hot pan and sprinkle with the remaining 1/4 teaspoon salt. Brown on one side, about 5 minutes, then flip and finish cooking, 3 or 4 minutes longer. Remove to a cutting board. Put the reserved sliced onion in the skillet to reheat. Scrape up any brown bits stuck to the bottom of the pan.
6. Wrap the tortillas in damp paper towels and microwave on high 1 minute. Remove the paper towels and keep the tortillas warm. Cut the chicken across the grain into 1/4-inch slices and toss with the onion in the pan. Serve with tortillas and guacamole.
You can complete all the elements of these tacos hours before serving. Press plastic wrap directly onto the guacamole so it won't brown. Slice the chicken and put it in the skillet with the onions, ready to reheat.
Nutritional Facts per serving
Calories 421.4 cal
Fat 23.2 g
Saturated fat 2.5 g
Cholesterol 54.8 mg
Sodium 476.6 mg
Carbohydrates 29.6 g
Total sugars 2 g
Dietary fiber 6.8 g
Protein 26 g
Recipe use courtesy of Rick Bayless.