1/3 cup fresh lime juice
1/4 cup tequila
2 cloves garlic, minced
1 tablespoon chopped cilantro
1 teaspoon dried, crushed Mexican oregano
2 teaspoons ground cumin
1 teaspoon freshly ground black pepper
Whisk together lime juice, tequila, garlic, cilantro, oregano, cumin, and pepper in a bowl.
To use the marinade, pour into a resealable bag, and add 1 to 1 1/2 pounds of flank steak. Press the air out of the bag and seal tightly. Marinate in the refrigerator 8 to 24 hours.