1. Rinse liver and remove thin outer membrane (if there is any). Slice the liver into 1/4 to 1/2 inch thick slices.
2. Soak the liver slices in milk for 1/2 - 1 hr.
3. Cut the onion into rings and then cut the rings into quarters.
4. In a large skillet over medium heat, heat 3 tablespoons oil.
5. Dredge the liver slices in flour and brown (for about 3 minutes per side).
6. Season to taste with salt and pepper. Add onion and cook until onion is soft (about 5 minutes). Be careful not to overcook, or liver will be tough.
7. Serve with mashed potatoes or any other of your favorite side dish, to taste.