Heat your oven to 350°F. Set a wire rack on a baking sheet or inside a roasting pan. Take the turkey out of the fridge and let it sit on the counter for 30 minutes. This helps it cook evenly, so the outside doesn't dry out before the center is done.
In a bowl, mix the softened butter, brown sugar, salt, pepper, smoked paprika, oregano, and garlic. Stir until you get a smooth, spreadable paste with no butter lumps. I like to taste a tiny bit of the paste, because it should smell rich and a little smoky.
Set the turkey on the wire rack. Gently loosen the skin with your fingers. Push some of the rub under the skin, then spread the rest all over the outside. Don't rush this step, because the butter is what keeps the meat so moist.
Slide the pan into the oven and roast for about 90 minutes for a 3 to 4 lb breast. Rotate the pan once halfway through so the turkey browns evenly. Check the thickest part with a thermometer, and pull it out when it reads 165°F.
Move the turkey to a cutting board or leave it on the rack for 30 minutes. Don't slice it early, or the juices will run out and the meat will turn dry. Use this time to make the gravy, so everything is ready together.
Pour the pan drippings through a fine mesh sieve into a bowl. This catches the larger bits so your gravy turns out silky and smooth. Keep those drippings, since they hold all the roasted flavor.
Add the stock and flour to a shaker cup and put the lid on tight. Shake hard for at least 30 seconds until the flour is fully dissolved. This step is the secret to a lump-free gravy.
Heat the drippings in a saucepan over medium heat. Slowly whisk in the slurry. Keep stirring and scrape the bottom of the pan often as it simmers. It takes 10 to 20 minutes to thicken, so be patient and keep whisking.
Taste the gravy and add salt and pepper if it needs it. Keep it on low heat and stir often until you are ready to serve. Slice the turkey, pour the gravy over the top, and finish with fresh herbs.