Here's what I do just about every year and I always end up with requests to do it again. I've been frying turkeys for a long time now - long before it became the popular method it is today. Over the years my methods have changed, but this is the basic method that is the framework. You are free to modify what you want on seasonings, or not follow it at all. Your choice.
SAFETY: Cook the damned bird outside. Away from structures that can catch fire. Don't have kids or dogs around. You need a place that doesn't have a lot of wind blowing either. Thaw your turkey. Wear PPE (gloves and closed toed shoes). Don't be an idiot - you are dealing with a few gallons of boiling oil and an open flame. Burn scars don't go away.
1. Obviously, ensure your turkey is completely thawed. Very important. Not so much for safety (birds don't explode like the myth, but a frozen bird won't cook and you will be shamed for all eternity). Remove the neck and gizzards package and hand them to the missus to begin the gravy process. Remove the plastic cooking indicator and the plastic hangar they use at the slaughterhouse.
2. Take your thawed turkey, put it in your pot. Fill pot with water until the turkey is just covered. Let the bird sit in the water for 3-5 minutes, top off as necessary and wait a couple of more minutes. (this allows the water to fill up the cavity and get in all the nooks and crannies). Remove turkey, let it drain for 3-5 minutes OVER THE POT, then mark the outside of the pot where the water level is. This is your oil fill level for that bird.
3. Injecting the marinade: I typically use Cajun Injector brands - Creole Butter and Garlic Butter flavors are the most popular in a 50/50 mix, but other flavors and brands work as well. I mix the two together and inject multiple places. Be sure to use small injection pockets - large pockets tend to burn and ruin the flavor of the meat. I also inject from the inside of the carcass so that the injector doesn't ooze out nearly as easily as it does if you inject on the outside.
Inject in 10 to 12 different places. When you are done, massage the bird all over for 3 or 4 minutes to work the marinade in and keep any large pockets from standing. Massage the bird, love the bird. Talk dirty to the bird.
4. Tony's - get 2 cans. Use 1 can on the outside of the bird. Don't worry about putting too much on as much of the seasoning cooks off when it's frying. Once you are done with that, take the other can and dump it in the organ cavity (all of this is obviously after removing the neck and gizzards and the plastic baking indicator). Dump it in there liberally - these seasonings will help flavor the meat from the inside out. Again, it's really almost impossible to put too much as most of the seasoning cooks out. It seems like a waste, but it works.
(Note 1: you can use just about any seasoning you want, the pre-made injectables and something like Tony's are already made, easy, cheap and work really really well though. I usually add some other stuff, but that's personal flavor likes for me)
(Note 2: some people brine their turkeys. I don't see any point in brining something that is getting essentially boiled in hot oil. Brining helps hold in moisture, which is a great thing for smoking or baking, but if your fried turkey comes out dry, well, you pretty much FUBAR'd it and probably need to just give it to the dogs and head over to Boston Market wearing a large S on your shirt for "shame")
5. Let the bird marinade in the fridge for 24 hours to 48 hours. 48 Preferred. Put it in your turkey pan and wrap up tight in saran wrap.
6. Cooking - take your pot and clean it. Don't be afraid to clean it 2 or 3 times. You want to ensure that all dirt, oil, grease, etc. is cleaned out to prevent anything like this from burning and ruining your bird. A clean pot is a happy pot. A clean pot makes a good bird.
(Note 1: clean the damned lid and thermometer also)
7. Fill pot with cottonseed or peanut oil to your mark on the outside of the pot. Heat to 350. This will take a while, but keep your eye on it - once it hits 250 or so, the temp starts to shoot up pretty quick. Around 375 and the oil will start to burn, and that's bad. Not flame up burn, but leave a bitter flavor burn. Fame up burn is bad too, but I hope you realize this already. Don't let either happen.
Once your oil hits 325-350, take a couple of potatoes and slice them up (bread also works - basically you want the starches) and toss them in the oil. Potato works best because you essentially make chips, and they are great to snack on while you cook. The starch helps condition the oil and removes any bitter taste that may be present. I season my potato slices with salt, because hey - I loves me some salty potato chips.
SLOWLY drop bird into oil when it's reached the right temp. What part of SLOW don't you understand? SLOW - take 2-3 minutes to get the entire bird submerged.
Remember that your temp will drop to about 300 when you first do this - it is important to not freak out and make massive adjustments to your heat input, otherwise when everything stabilizes you are going to have the oil too hot and end up either burning your bird or you'll spend the entire time adjusting up and down trying to regulate the temp. After about 5 minutes, if you need to increase the heat, make small adjustments until you hit your target temp.
(note - some folks turn off the flame here. That's not a bad idea. I've never had a flare up or overflow, but I take 2-3 minutes to put the bird in - welding gloves are a good thing to have here)
8. Boil/Fry at 350 for 3 minutes per pound. If you cook at 325, add another 1/2 minute per pound. Most birds are in the 12-15 pound range, so you are looking at roughly 45 minutes in the pot.
9. When your bird is done, remove from oil and hold it over the pot for a minute or so to allow the residual oil to drain out. Not doing so can leave you with a soggy bird that isn't nearly as good. That and when you put the bird on the cutting board or basing pan to sit, the oil you didn't let drain out will drain out and you'll have drawn the ire of the missus for the mess you made in her kitchen.
10. This is very important: Let your bird sit for 10 minutes before carving. I use a large cutting block for this, but you can use a basting pan. This lets the last bit of residual oil to drain out, lets the bird finish cooking and start cooling down. Odds are you'll have to keep people away, but if you don't let it sit, the bird generally ends up soggy and not nearly as good.
11. After 10 minutes, carve and serve. Then bask in the glory of being the cook. Reminder - the bird is still hot. Don't forget this.
12. After everybody is fat and happy and has taken the requisite Thanksgiving day nap, take the bones and put them in a pot, covered with water. Simmer for a few hours and jar up the awesome turkey stock you have created. Next time you make a gumbo or etouffe, use some of this stock. Again, you will have to be humble in the praise you will get from the masses, so keep that in mind.
