Heat 1 tbsp. oil in large skillet over medium-high heat. Season steak with Adobo. Cook steak, flipping once, until dark golden brown on both sides, about 4 minutes; transfer to plate. Add onions and garlic to pan. Cook, stirring occasionally, until onions begin to soften, about 3 minutes more. Add beef bouillon mixture to pan; bring to boil, scraping up any browned bits from bottom of pan. Return steak to pan; Reduce heat to low. Simmer, covered, flipping steak occasionally, until meat shreds easily with fork, about 2 hrs. Transfer steak to cutting board, reserving juice in pan. Shred steak; transfer to bowl and set aside. (Note: Shredded steak can be stored covered in refrigerator for up to 5 days.)
Heat medium skillet over medium heat. Add chiles. Toast, turning once, until fragrant and slightly puffed, about 4 minutes. Transfer chiles to medium heat-proof bowl. Cover with 1 cup boiling water. Let soak, turning chiles occasionally until soft, about 30 minutes. Transfer soaked chiles, ½ cup chile soaking liquid, lemon juice, salt and 1½ cups reserved liquid and solids from pan to blender (discard remaining liquid from pan). Blend until completely smooth, about 2 minutes. Transfer chile sauce to small saucepan over medium heat. Bring chile sauce to boil; reduce heat to low. Simmer, stirring occasionally, until sauce thickens slightly, about 5 minutes; remove from heat. (Note: Sauce and be stored covered in refrigerator for up to 5 days).
Heat oven to 350°F. Mix shredded beef with ½ cup chile sauce; set aside. Set aside remaining chile sauce. Heat remaining oil in medium skillet over medium heat. Using tongs and working with one tortilla at a time, dip tortilla in oil; cook until warm and soft enough to roll, about 5 seconds. Drain tortilla, allowing excess oil to drip back into skillet. Transfer tortilla to plate. Spoon some reserved chile sauce on tortilla and flip to completely coat both sides. Place some reserved meat into center of tortilla; roll up enchilada. Arrange rolled enchiladas, seam side-down, in baking dish. Top with any remaining sauce. Transfer enchiladas to oven and heat until warmed through, about 10 minutes. Sprinkle with lettuce, cheese and crema; serve.
The assembled enchiladas can be stored, covered, in refrigerator for up to 3 days. To reheat, drizzle with 1 tbsp. water, cover with foil and heat in 300°F oven until warmed through, 20-25 minutes.