1-2 days before you plan to cook the turkey, pat the Whole Turkey (10 pound) dry with paper towels. Sprinkle the Kosher Salt (1/4 cup) all over the outside of the bird, making sure to get into all the crevices.
Loosely cover with plastic wrap and place in the fridge for at least 12 hours, up to 2 days.
On the big day, preheat the oven to 450 degrees F (220 degrees C). Adjust the rack to the middle position.
Spatchcock the bird by first placing it breast-side down on a stable surface, then cutting around the sides of the backbone with poultry shears. A sharp knife may also be used, but this has the potential to damage the blade, so make sure to be careful.
Once you’ve removed the backbone, set it aside for later. Flip the bird over and spread out the legs. Finally, press down forcefully on the breastbone to flatten the bird. Tuck the wing underneath the breast.
To make the compound butter, pick the leaves off a few sprigs of Sage Leaves (1/4 cup) and Fresh Thyme Leaves (1/4 cup) - you want around 1/4 cup of each.
Finely mince the sage and thyme leaves. Feel free to pop them in the food processor if you're worried about your chopping skills.
Finely mince the Garlic (3 clove). Remove the end, lightly crush it with the flat side of the knife, then slice lengthwise and into a fine mince.
Combine the sage, thyme, garlic, and Ground Black Pepper (1/2 teaspoon) with the Unsalted Butter (1/2 cup) in a small bowl.
Prepare a rimmed baking sheet with half the Celery (2 1/2 stalk), Carrot (1 1/2), and Onion (1). If desired, drizzle with a few splashes of Dry Vermouth (1/2 cup). Place a wire rack on top.
Move the turkey to its final resting place atop the wire rack.
Working to slowly loosen the turkey skin with your fingers, gently push HALF the herb butter up under the turkey skin as much as you can manage, especially under the breasts and thighs. Massage the skin to help evenly distribute the butter.
Microwave the remaining butter mixture for 30 seconds to melt, then brush all over the outside of the turkey.
Roast the turkey for 60-80 minutes, or until the thickest part of the thigh reaches 165 degrees F (75 degrees C) according to a pen thermometer.
While the turkey cooks, let’s get going on the gravy. First, chop that reserved backbone into 3-4 pieces.
In a large saucepan, heat up a generous splash of Olive Oil (1 tablespoon) over medium-high. Once hot, put the turkey backbone pieces into the pot skin side down and cook until browned, 3-4 minutes.
Add the Chicken Broth (1 quart), Water (2 cup), Celery (2 1/2 stalk), Carrot (1 1/2), Onion (1) and extra sage and thyme and bring to a boil, then let simmer for around 1 hour, or until the turkey is done cooking.
Once the turkey is done, move the wire rack with the turkey to a new baking sheet and let it rest for 20 minutes.
Take the baking pan that the turkey was on and scrape all of the drippings and veggies into the simmering stock. Stir to combine and let simmer for an additional 5 minutes.
Strain the stock. To avoid spilling, remove some of the larger pieces first.
It’s time to make our roux for the gravy. In a saucepan (using the same one is fine), melt the Unsalted Butter (1/4 cup) over medium heat. Add the All-Purpose Flour (3/4 cup) and whisk to combine, continuing to stir for 1-2 minutes to cook the flour. The mixture should be crumbly at this point.
Add in 3-4 ladles of stock, whisking to combine between each one. The mixture should become a homogenous paste.
Add in the remaining stock and continue to whisk. Taste and adjust seasoning as needed. I like to add a generous sprinkle of ground black pepper, but it won’t usually need any more salt since you added all the turkey drippings. Simmer until desired thickness is reached, 5-10 minutes.
By now your turkey will be ready to carve and your gravy ready to serve! Serve it all up on a pretty serving plate with boatloads of gravy and all the other delicious sides.