1 pound white onions, sliced into 1-inch-thick rings
½ pound fresh jalapeños
10 garlic cloves
1 tablespoon kosher salt
For the carne asada:
2 jalapeños, stemmed, seeded, and roughly chopped
6 garlic cloves
1 pound white onions, peeled and chopped
2 tablespoons salt
1 teaspoon freshly ground black pepper
6 ounces Mexican beer
4 ounces water
1 (2-3 pound) top sirloin
For the guacamole:
2 firm-ripe avocados, halved, pitted, and peeled
½ cup diced Roma tomatoes
¼ cup diced white onion
2 tablespoons lime juice
2 tablespoons minced fresh cilantro
1 tablespoon minced fresh jalapeño
1 package tostadas
½ cup Oaxaca cheese, shredded by hand
Cilantro for garnish
1. Make the salsa molcajete: Preheat oven to 350 degrees. Heat grill to 375 degrees (medium-high heat) and char tomatillos, tomatoes, onions, and jalapeños, then place in an oven-safe pan and cover ¾ the way with water. Cover with foil and roast in oven for 30 minutes.
2. Carefully transfer contents from roasting pan to a blender and blend until chunky. Add garlic and salt and continue to blend. Transfer to a bowl and set aside.
3. Make the carne asada: In a blender, combine first seven ingredients and puree until smooth. Pour over sirloin and marinate in refrigerator for 3 to 4 hours. Heat grill to 375 degrees (medium-high heat) and grill meat for 6 to 8 minutes per side for medium.
4. While steak cooks, make the guacamole: In a bowl, mash avocado, then stir in remaining ingredients. Add salt to taste, cover, and set aside.
5. To assemble: After steak has rested for 5 minutes, slice very thin and set aside. Place tostadas on a sheet tray and layer with steak and cheese, then broil until cheese has melted. Move to a serving platter and garnish with salsa, guacamole, and cilantro.