Place the beef tongue in a crockpot, and fill it with enough water to cover the tongue. Add onions, 1 tbsp. garlic, oregano, cumin, and salt. Cook on high for 4-6 hours, or on low for 6-8 hours until the tongue is soft to the touch and tender. Once it’s tender, take the tongue out of the crockpot.

Peel off the outer layer of the skin when you are able to handle the tongue. It’s easier to take the skin off while the tongue is warm. Dice tongue into 1⁄2-inch cubes and set aside.

Heat oil in a pan, add lengua (tongue) cubes, and 1 tbsp. minced garlic, and cook until a little crisp. Warm the corn tortillas.

Place lengua in warm corn tortillas, add Tomatillo Salsa Verde, diced onions, crumbled cotija cheese, and avocado slices.