½ bottle Mexican beer
Juice from four limes
2 cloves garlic, finely minced
2 tablespoons finely minced shallots or onion
Kosher salt and pepper
2-3 pounds of trimmed skirt steak
In a bowl, whisk the first four ingredients together. Add salt and pepper to taste. In a gallon-sized bag (or several, depending on the amount of steak), pour the marinade over the steak. Let sit overnight in the refrigerator.
Bring steak to room temperature before cooking. Sprinkle with salt and pepper. Cook over a preheated grill to desired temperature (for example, medium -- it's hard to go lower when it's trimmed so thin). Serve with tortillas and taco fixings.