Behold, my super-relaxed, don't-fret-about-details-too-much guide to roasting a tasty turkey.
A defrosting/cooking guide: (note: these times are for defrosting in the fridge - if you don't have enough time, you can leave it in a sink which will speed up the process, you just have to be ready to cook it right away. In a super emergency, you can soak it in warm water to speed it up even more.)
A 2 - 2.5kg turkey will need 20 hours of defrosting time and 1 1/2 hours cooking time (plus resting).
A 4 - 4.5kg turkey will need 24 hours of defrosting time and 3 hours cooking time (plus resting).
A 6.5 - 7.5kg turkey will need 28 hours of defrosting time and 4 1/2 hours cooking time (plus resting).
A 9 - 10kg turkey will need 40 hours of defrosting time and 6 hours cooking time (plus resting).
Always weigh the turkey after you have stuffed it. When cooked, the skin should be crisp and the juices run clear.
So, how to cook a turkey (or any other bird): take it out of the plastic, and wash it inside and out. If it comes with a neck/giblets inside, pull them out and stick them in a small pot to make gravy with. If the bird is still icy inside, just keep running water pouring through the cavity to help thaw it out.
Preheat oven to 180°C.
Pat your bird dry with paper towels, put it in a baking tray large enough to fully contain the sticky-out bits. Fold the wing-tips under the bird in some freaky poultry-oragami kind of way. If you're going to stuff your bird, now is the time! Packet stuffing mix works just fine, but remember that you can pretty much stuff your bird with whatever you like. I like a mix of rough-chopped apples, bacon, onions and garlic mixed through with some sage and soy sauce. If you're using a bread-based stuffing, don'y cram it in there too much or it won't cook all the way through. Anything fruit-based is fine, because the watery fruity bits will heat faster than bread.
Fold over the skin at the front and rear ends of the cavity and seal shut by weaking a skewer through the skin or, if you're feeling fancy, by sewing the bird up like a Tim Burton horror-themed shoe. It's a good idea to tie the legs together here as well, so they don't flail about as you cook.
The seasonings here are a general guide, but this is what I like to do: rub the bird all over with butter. Hey, it's Christmas, live a little. Prick the skin all over with a skewer or sharp knife, just enough to make holes in the skin, not pierce the muscle below. By all over, I mean it - breast, thighs, back, wings, legs. Lay the bird on its back, and rub the boob with whatever spices you like - sage is always a good bet, but anything like rosemary, allspice, mixed-spice, some unlabelled bottle of green in the back of your pantry, or pepper will do. I like to give the bird a healthy splash of soy all over, or you can salt it if you prefer.
Loosely cover the bird with foil, then put it in the oven. Baste it with juices from the pan every 30 mins - just take it out, use a spoon to scoop up the tasty juice, pour it over the skin a few times, then put it back in the oven. About half an hour before it's finished, remove the foil from the bird to let it brown up.
Check that it's cooked by stabbing it in the little pocket between leg and body - if the juices run clear, it should be done. If in doubt, you can always leave it in the oven a little bit longer, and remember that it continues to cook when it's out of the oven. Take it out of the oven, cover it with foil, and let it rest for a minimum of 20 mins before carving.
Gravy notes! Take your neck/giblets, put them in a pot with a quartered onion, a stalk of celery (cut in half), a carrot or two, or anything else you have near by. Cover with water and boil for a while to make some stock. When the turkey comes out of the pan to be carved, put the pan full of juices on the stove on a low heat, and pour in the stock to deglaze the pan. Stir it as it boils and let it reduce to a tasty sauce. You can add a dash of milk to enrich it, or some cornflour to thicken it, but either way it will be tasty.
And there you have it! Cooking a turkey really isn't much of a hassle, it just takes a bit of time. Enjoy! :)