1. Halve avocado lengthwise and remove seed; then peel. Slice the avocado and coat pieces with lemon juice; set aside.
2. In a bowl, mash remaining avocado half.
3. Stir in chile peppers, egg, onion, the remaining lemon juice, garlic and salt.
4. Add beef and combine thoroughly (mixture will be moist).
5. With your hands, shape meat into 4 patties, each about 3/4 inch thick.
6. Microwave a 10-inch browning dish or skillet on HIGH (100%) for 4 1/2 minutes.
7. Carefully remove dish (the bottom is very hot) to a heat proof surface.
8. Place patties in dish. Microwave, uncovered, on HIGH (100%) for 3 minutes. Drain off fat.
9. Turn patties over. Microwave, uncovered, on HIGH (100%) for 2 minutes or until juices run clear when patty is slashed.
10. Sprinkle each patty with 2 tablespoons of the cheese. Cover with wax paper and let stand for 5 minutes.
11. Arrange patties on bottoms of buns and top each patty with lettuce leaves, tomato slice, and a few avocado slices.
12. Cover with remaining buns. 

*Large avocados are recommended for this recipe. A large avocado averages about 8 ounces. If using smaller or larger size avocados adjust the quantity accordingly.