For the butter, mince the garlic. Mix all of the ingredients together in a small bowl.
Preheat the oven to 170C/325F.
Rinse the turkey inside and out. Pat the skin dry and place in a roasting rack inside a large roasting pan.
Chop the onion and celery. Slice the lemon into wedges. Mince the garlic.
Stuff the cavity of the bird with the veggies from step 4.
Loosen the skin of the bird by putting your hands between the skin and the breast meat working your way down the leg. Take some of your butter mixture and rub it thoroughly under the skin over the breast and leg meat. Coat as much as you can. It's easier if the butter is at room temperature.
Pour the olive oil all over the turkey and sprinkle the salt and pepper all over. Tie the legs of the turkey together with kitchen twine or oven proof string. Put a probe thermometer into the thickest part of the breast (if you have one).
Place the turkey breast side up into the oven on the middle rack and bake for 2.5 hours to 3 hours. Halfway through, baste the turkey juice all over the skin. At 2.5 hours, check the thermometer. It should register at 160F/71C. If you don't have a probe thermometer, open the oven and check with a handheld thermometer. If it's not there yet, cook it a bit longer (10-40min).
Once the breast meat registers at 160F/71C, take it out of the oven and cover the dish with aluminum foil for 30 minutes. This will finish cooking it.
After that, you can start carving it!
Honestly, I don't really know how to count the nutritional value in this. A "whole" turkey doesn't appear in any of the calorie counting websites...sorry guys! *My small Japanese oven is too small for a turkey rack and even the turkey itself, so I just put it in an aluminum tray large enough to catch all the drippings. For the gravy recipe, I have two recipes up on the blog. A Paleo Turkey Giblet Gravy that is dairy-free and thickened with tapioca starch, or a Keto Turkey Giblet Gravy that is not dairy-free and thickened with xanthan gum. Both recipes are keto/low carb.For the cranberry sauce recipe, check it out here!