What is that yellow and white stringy stuff on your tacos?I bought a beef heart for my dog from a local processor. Decided to slice some thin and sear it in a cast iron skillet with some garlic and salt and hit it with some mojo sauce to finish. Made outstanding tacos. Unfortunately, this is the sort of thing I only get to fix when my wife won’t be eating with me. i don’t understand why they don’t sell these in Mexican restaurants.