• Step 1: In a large skillet or cast-iron pan, heat the olive oil over medium-high heat. Add the sliced onions and sauté for 5-7 minutes, stirring occasionally, until they start to caramelize and become translucent.
• Step 2: Reduce the heat to medium-low and continue cooking the onions for an additional 10-15 minutes, stirring frequently, until they are deeply browned and caramelized. Transfer the onions to a plate and set aside.
• Step 3: In the same pan, increase the heat to medium-high. Add the beef liver slices and sear for 2-3 minutes per side, or until they are lightly browned on the outside but still slightly pink in the center. Be careful not to overcook the liver, as it can become tough and dry.
• Step 4: Return the caramelized onions to the pan with the seared liver. Add the minced garlic and dried thyme, and season with salt and black pepper to taste. Stir to combine and cook for an additional 2-3 minutes, until the garlic is fragrant and the flavors have melded together.
• Step 5: Serve the beef liver and onions hot, garnished with additional fresh thyme or parsley, if desired. Enjoy this delicious and nourishing dish with your favorite sides, such as mashed potatoes, roasted vegetables, or a fresh green salad.