Start by thinly slicing the top round steak into about a ½” or less thick slices.
Place the slices between two sheets of parchment paper and gently pound them with a meat mallet until they’re about ⅛ to ¼ inch thick. For extra tenderness, you can also run a Jaccard over each slice with several passes.
Season the tenderized, jaccarded beef with salt and pepper on one side and place in a large bowl.
In a food processor or with a mortar and pestle, finely mince or grind down the garlic until it resembles a paste. Add the oregano and continue until it is fully incorporated into the garlic paste. You want it this fine so it spreads easily throughout the beef.
Next, add the oil and vinegar and mix to combine.
Add the garlic, vinegar, and oil mixture to the bowl with the sliced beef, and very gently mix until each piece is completely coated. Take care not to tear the beef.
Next, add in the sliced onions and continue mixing. Cover and refrigerate for 1 to 24 hours. The longer you can marinate, the more flavorful it will be.
When you’re ready to cook, remove the steak from the onions.
In a large frying pan, add 1 tablespoon of lard and heat over medium-high heat.
Once it begins to smoke, add as many marinated beef slices as possible, without overlapping, and sear just 1 to 1 ½ minutes per side or until lightly browned. Set them aside on a plate, and repeat the process with the lard and beef slices until everything is seared. Be sure to watch if the heat is too high and things seem to be burning. You may have leftover lard depending on the size of your pan.
Place the onions in the pan and saute for 8 to 10 minutes or until they start to brown.
Turn the heat down to low-medium and continue cooking, stirring occasionally, for 10 more minutes or until caramelized. If you notice the onions are looking dry or are sticking, deglaze with a few tablespoons of beef stock.
Adjust the seasonings with salt and pepper.
Add the steak back in, along with all its juices; it’s ok if it’s stacked up. Cook for a few minutes to reheat everything.
Serve the caramelized onions and juices over the steak.
Notes
It’s important to give the beef lots of love when we’re making bistec encebollado, especially if you’re using a tough, lean cut, as I did. I always start by slicing the top round roast against the grain to break up the long muscle fibers. Then, I flatten the pieces with a meat mallet. I finish by tenderizing them with a Jaccard (or stab them all over with a fork). These steps help the marinade soak into the fibers, making every piece tender and packed with flavor.Marinating time: I always try to prep this recipe at least 24 hours in advance so the meat can marinate overnight. But when I’m rushed, I’ll settle for a 1-hour minimum.Don’t overcrowd the pan: I sear the steak in batches to help the slices form a rich, brown crust on the outside. Dumping all the meat in at once will only lead to soggy steak.Don’t burn the onions: Slicing the onions into uniform rings or a thick julienne keeps them from cooking too quickly. If they start browning before they soften, don't be afraid to kill the heat. We want them jammy and sweet to contrast the savory, garlicky beef. How to Store: Cover the leftovers and store in an airtight container in the fridge for up to 4 days. You can also freeze the steak and onions for up to 2 months. Thaw them in the fridge overnight before reheating. How to Reheat: To keep the meat tender, reheat the steak and onions in a skillet over medium-low heat with a splash of beef stock. Cover the pan to let the steam warm the beef through for a few minutes.