Me, I prefer a white for the reduction (red to drink with dinner) but you can go with red for the sauce if you prefer.
Make a paste out of garlic - run 6-8 cloves through a press - plenty of ground black pepper, a couple teaspoons of fresh thyme leaves (or a teaspoon of dried), a couple teaspoons or fresh rosemary leaves, minced (I don't recommend using dried), 2 teaspoon of granulated onion, a half-teaspoon of granulated garlic, and a half-teaspoon of coriander. Mash well together adding a half-teaspoon of Dijon mustard, a tablespoon of olive oil and a tablespoon of softened butter. If not thick enough -you want a just-spreadable paste - add some more granulated onion and/or granulated garlic and/or black pepper to thicken. Stir in a pinch of salt if the butter you used was unsalted.
Allow the roast to sit out for 30-60 min. Set your oven (or get your grill going) to 375-400?.
Sprinkle the roast with salt on all sides. Spread the paste on the roast. If you have a flack rack that will fit the pan, oil it lightly and place it in the pan. If not, cut an onion so that you will have 2 thick (about an inch) slices. Cut a celery rib into quarters crosswise. Place two onion slices and two pieces of celery in the pan so that the roast sits on top of them, as a rack. (You can also use all onion or all celery.)
Place the roast into the hot oven (or grill). Cook about 30-35 min, if typically sized, to an internal of 130?. If needed, add a splash of water to the roasting pan from time to time to prevent any drippings from burning.
Remove the pan, and remove the roast to a large piece of foil, cover with another piece, and let rest 15-20 min.
Meanwhile, deglaze the pan with the wine of choice, using about a cup and letting it reduce to 3-4 tablespoons. Stir in 1 cup of low-salt chicken stock, some freshly ground pepper, and .5-1 teaspoon of minced fresh rosemary. Remove the onions and celery, if using. Reduce this by 1/4, so that you have about a cup. Pour into a small pot then, off heat, whisk in 2 teaspoons Dijon mustard till smooth. Immediately whisk in 2 tablespoons unsalted cold butter, one tablespoon at a time, allowing each pat of butter to slowly melt into the sauce as you whisk.
Remove the roast to a platter, pouring any collected juices from the foil into your sauce pot. Fill with potatoes, if desired, making a small well to hold a couple tablespoons of sauce and, perhaps, a sprig of rosemary or thyme. Serve, passing the remaining sauce separately.
Just a thought.
