Remove any silver membrane you see on the liver. It is a thin silver or whitish coating on parts of the meat. You can easily remove it with a small knife.
Cut liver into 2-inch pieces, or smaller.
Rinse the liver under cold running water and pat dry with paper towels.
Place the liver in a bowl of milk to soak in the fridge for at least 1 hour.
While the liver soaks, heat two tablespoons unsalted butter or oil in a large skillet over medium heat.
Sauté the onions until soft and golden brown, stirring occasionally, about 10 minutes.
Remove the liver from the milk when the onions are nearly cooked. Pat dry.
Season both sides of the liver with salt and pepper.
Melt 3 tablespoons of butter or oil over medium-high heat. Add the liver to the pan without crowding it. Cook the liver for 2-3 minutes per side.
Remove the liver to a plate and top with the sautéed onions.
Garnish with chopped parsley and lemon wedges.
Notes
For Keto or Low Carb: If you're on a keto diet, use only 1 onion or no onions. You can add garlic to the pan while cooking the liver for extra flavor.For Paleo and Dairy-Free Diets: Skip the milk soak. Veal liver can be cooked without soaking and still taste great!Leftovers: Store any leftover veal liver and onions in an airtight container in the refrigerator for up to 2 days. Reheat gently in a skillet over medium heat before serving.