I discovered vaca frita (literally -- fried cow) in a short-lived and long-mourned after it closed Cuban restaurant in midtown Memphis, a few years ago.
Ingredients
2 pounds flank steak
2 onions
1 teaspoon salt
6 cloves garlic
1 bay leaf
1 teaspoon cumin
3 tablespoons chopped fresh oregano
juice of three limes
2 tablespoons neutral flavored oil
Directions
Put about two quarts of water on to boil in a large Dutch oven. Add the bay leaf, one onion, quartered, the salt, and three of the cloves of garlic, smashed flat with the blade of a knife.
When the water boils, cringe, grit your teeth, and drop the raw flank steak in. It feels wrong. It really isn't. Boil until it's completely done, about 30 minutes.
Fish the grey chunk of flank steak out onto a cutting board. Strain the veggies out of the stock, and put it aside for future use.
When the flank steak is cool enough to handle, shred it, discarding the gristly bits and any fat.
In a bowl large enough to accommodate the shredded beef, mix the lime juice, cumin, and the remaining garlic, finely minced. Add the beef and the fresh oregano, which you have minced. Give it a few good tosses to make sure the lime juice coats the beef shreds well, and go away and leave it to marinate for an hour or so on the counter.
Peel and halve the other onion, then thinly slice it. Heat a cast iron skillet or grill pan over high heat, add the oil, and the onion slices. Stir and toss until they're starting to get translucent and a little brown in spots.
Add the beef. Stir and toss until the beef starts to get browned and crispy in spots. How browned and how crispy are up to your personal taste. Depending on how much beef you have and how large your skillet is, you may want to do this in two batches; it browns easier and more quickly if it's not crowded.