The liver from wild-game animals has traditionally been consumed in deer camp. More often my game livers are extracted, frozen whole and eaten at home. While deer liver is generally considered safe to handle, it is no great trouble to slip on a pair of rubber gloves when cutting and processing liver. Gloves must be used when handling hog and bear livers as these can contain blood-born parasites that can cause serious diseases.
That caution given, remove the gall bladder (free in deer liver, attached in hog liver) and the pancreas before freezing. I wash the liver to expel any excess blood and remove any surface contamination. Cut away any parts that have been ruptured or cut by a bullet or arrow, but otherwise make few cuts, except to partition into one-meal portions.
Before cooking, allow the liver to semi-thaw and then cut into slices about 3/8ths- inches thick. Remove any large blood vessels that may still be attached. Start canola or olive oil heating in frying pan. Coat liver in flour, salt and pepper mixture. When oil is hot fry liver, taking care not to be hit by popping oil when you add the liver. Brown liver on both sides, remove and drain. Pour off excess oil. Some coating will be stuck to pan, let that remain.
Dice two medium Spanish onions and add to pan. Put on medium heat. Scrape pan with spatula until onions caramelize and any stuck-on residue is free. Return liver to pan and add water to cover. Allow liver to steam until tender. Serve hot with pan scrapings and onions on top.
As a variant, put left-over liver on bottom of dish and add cooked spinach with a sprinkle of cheese on top. Reheat for 15 minutes, garnish with sliced hard-boiled eggs on top and serve.
Small livers from geese and turkeys are incorporated into giblet
gravy (see recipe in my books Backyard Deer Hunting: Converting deer to dinner for pennies per pound and X-Treme Muzzleloading: Fur, fowl and dangerous game with muzzleloading rifles, smoothbores and pistols (Summer, 2010). Or crushed, the veins removed and mixed with mayonnaise to make a pate.
Huge livers from moose and the like, are often made into liver sausage.