In a large bowl, whisk together the lime juice, zest, garlic, Adobo Seasoning, chopped parsley, and ground black pepper; set aside. Using a rolling pin or a meat mallet, pound the beef tenderloins between 2 sheets of parchment paper until they are evenly ½ inch thick. Slice each beef in half crosswise, so you have two pieces approximately the same size; repeat with the rest of the beef. Place the pounded beef in the marinade, cover it with plastic wrap, and refrigerate it for at least 30 minutes.
Meanwhile, whisk the eggs, salt, and pepper until very foamy in a large bowl, about 3 minutes. Add the milk and gradually whisk in the flour until no lumps remain (batter should be smooth). Next, stir in the club soda, ½ half at a time, whisking to work out any lumps. The batter should be the consistency of heavy cream.
When ready to cook the beef, preheat the oven to 250 °F (121.11 °C). Place a sheet pan with a baking rack on it in the oven. Heat 3 inches of oil over medium-high heat using a large high-sided skillet. Add the plain flour to a large shallow bowl; set it aside. Once the oil is shimmering, working in batches, lift the beef from the marinade, allow the excess to drip off, dredge the meat on both sides in the flour, and shake off any excess flour.
Next, dip it well in the batter mixture, allowing the excess to drip off. Fry 1 to 2 Marinera de Carne at a time, leaving room between them, occasionally turning until golden brown on both sides, about 3 minutes per side, and gently pressing down on the meat to help ensure even browning. (The internal temperature of the meat should register 165 degrees on an instant-read thermometer). Be careful; the oil will splatter!
Do not overcrowd the skillet; the temperature of the oil will drop; adjust the heat as needed to keep the temperature at 350 degrees Fahrenheit. (I recommend using a Deep Frying Thermometer).
Remove with a fork and transfer the Marinera de Carne on a baking sheet lined with paper towels to drain excess oil before serving or transfer the Marinera to the sheet pan in the oven to keep warm. Let the oil temperature return to 350 degrees F before frying the remaining meat. Repeat the procedure with the remaining beef. Serve with “Fideo a la Manteca” Buttered Pasta. Yum!😍😋🍻