This recipe is inspired by Soy Parrillero MX. Beef sweetbreads, also known as heart sweetbreads, are one of the cow’s organ meats—specifically, the thymus gland. They are highly valued in Argentina, especially as an appetizer at barbecues. They’re usually cooked with plenty of lime and turn out crispy on the outside and tender on the inside. So what happens when you combine the best of both worlds and use them to make tacos? You realize they were meant to be together... forever!