Hamburguesas Mexicanas
1 head iceberg lettuce, cored and shredded 1 pound shredded pepperjack cheese 1 serrano chile pepper, minced, divided 1 ½ cups bread crumbs 12 hamburger buns 2 bunches cilantro, chopped 2 tomatoes, chopped and juices strained 3 limes, juiced, divided 3 onions, minced, divided 3 pounds ground beef 4 eggs 5 avocados, peeled and pitted salt and ground black pepper to taste