Prep the Liver: Rinse the beef liver slices under cold water, then pat them dry with paper towels. If you prefer, you can dredge the liver in flour seasoned with salt, pepper, garlic powder, and paprika. This is optional but adds a nice crispy coating.
Cook the Onions: In a large skillet, heat 1 tablespoon of olive oil or butter over medium heat. Add the sliced onions and cook, stirring occasionally, until soft and caramelized, about 10-15 minutes. Once done, remove them from the skillet and set them aside.
Cook the Liver: In the same skillet, add another tablespoon of olive oil or butter. Place the liver slices in the skillet and cook for 2-3 minutes on each side until browned but still tender. If you like your liver cooked more, you can extend the cooking time by a few minutes.
Optional: For extra flavor, deglaze the skillet with beef broth or Worcestershire sauce. Scrape the browned bits from the bottom of the skillet, then pour the liquid over the liver for added richness.
Serve: Return the caramelized onions to the skillet to warm through with the liver. Taste and adjust seasoning with salt and pepper.
Plate and Enjoy: Serve the beef liver and onions on a plate, garnished with fresh parsley if desired. Pair with mashed potatoes, rice, or a side salad for a complete meal.
