Method

1. Using your fingers, peel off and discard the thin membrane from the liver. Slice into thick finger-size strips. Transfer them into a dish, pour over the milk, cover, and chill for at least 30 minutes, to remove any bitter flavours. Pour off and discard the milk, rinsing the liver strips with cold tap water and briefly patting dry with paper towel. Set aside.
2. Dry-fry the bacon over a medium heat for 5 minutes. Transfer to a casserole dish.
3.  Add the onions and garlic to the same pan with a dash of oil and fry on a medium heat for 5 minutes, until softened and lightly browned. Remove from the pan with a slotted spoon and add to the casserole dish with the bacon.
4. Preheat the oven to 180°C.
5. Lightly coat the liver strips in a little seasoned flour, and lightly fry in two batches on a medium heat for 3 minutes, turning to sear all round. Add a little more oil if necessary. Transfer the strips to the casserole dish.
6. Stir the gravy powder into a little cold water and add to the pan with the hot beef stock, stirring until the gravy thickens and boils. Pour this over the ingredients in the casserole dish, cover and cook in the oven for 15 minutes.