Slice the liver in to bite size pieces.

Then in a large mixing bowl, add the flour and season with salt and pepper, add the liver and make sure each piece is coated with the seasoned flour.

Now take about 3 tablespoons of the remaining seasoned flour and place in a small bowl and mix with a little cold water to form a paste. This will be used later to thicken the gravy.

Cut up the bacon into small pieces and slice the onions, chop/crush the garlic etc. then over a medium heat, fry off the bacon until cooked. Remove the cooked bacon to a plate, leaving the bacon fat in the pan.

Now turn the heat up on the pan and add the liver slices. Carefully turn them until they are browned on all sides then remove on to a plate.

Add the sliced onions, garlic and mushrooms to the pan. Add a little more oil if required after cooking the liver. Gently cook until the onions are soft. If using herbs, add them now.

Add the bacon and liver back to the pan with the onions and mushrooms and combine. Now add the beef stock and tomato puree and beef stock together with the flour and water mixture you did earlier, stir well making sure everything is combined.

For cooking in the oven, transfer everything to an ovenproof casserole dish and place in the oven at 150 C for approximately 2 hrs 30 minutes.

For cooking in the slow cooker, transfer everything into your slow cooker and cook on low for 5-6 hours.

For cooking on the stove top, place the lid on the pan and gently cook on the lowest heat setting you have for about 2 hours or until the liver is tender.