2tbsp White vinegar (good for tenderizing any meat)
About a cup or so of onions.
Take the thawed deer meat and put it in a grocery bag, double bag it, a sturdy ziplock bag works well too. Take a hammer and beat the dear meat. This helps tenderize it and takes some of the chewy-ness out. This can get messy. Make sure to sanitize your counter before and after doing this.
Put the meat in a bowl and cover it with water. Put enough soy sauce into the water so that it is the color of soda. Add the 2 tbsp of white vinegar. Let it sit and marinate until the meat darkens. Make sure to stir it ever so often to let the marinade get on all of the meat.
After your meat has marinated (I usually let mine sit overnight in the fridge), chop up your onions (there's really no limit but I usually end up using a whole small sized onion) and sautee it in butter. Probably about 3 tbsp. Lay the meat in the pan on top of the onions. I like to throw a little extra soy sauce in with the butter as well as a little bit of water. This keeps it from drying out. Cover and let it simmer. Flip, cover and simmer again. Adding more soy sauce and water if needed. Do not salt this because the soy sauce does that. When it's done, you can drain it with a strainer or you can lay it on napkins.
It's so extremely good. Trust me. It doesn't taste gamey at ALL. So good.
Also, you can use the same method, minus the water, if you want to batter fry it. Sautee the onions in butter seperately though and just batter the deer and fry it in vegetable oil.