Cooking with Wine

Prepare the Beef
Completely pat dry your beef tenderloin. Tie it with butchers’ twine in 3-5 places to ensure the roast stays uniform. Set aside.
Prepare your garlic by thinly slicing the peeled garlic cloves. Heat a small pan on medium heat and add the 3 Tbsp of butter. Once the butter has melted, add the thin slices of garlic and sauté for just a minute or two. The garlic should not brown (a little around the edges is OK) but should cook enough that it sweetens up and loses the bitterness of raw garlic. Remove the garlic and discard the butter or save for another use (garlic butter!).
Using a thin, sharp knife, make holes in the tenderloin roast. Slide the garlic and/or thyme tips down the knife and, if needed, use your finger to push the garlic/thyme deep into the cut. Do this in various places of the tenderloin (top, bottom, and sides). Most or all holes can have both garlic and thyme, but some can just have one or the other if you wish. Place the meat on a rack over a sheet-tray, uncovered, in the refrigerator for several hours before roasting or up to 2 days to air dry and age.
Preheat your oven to 300°F
When ready to cook, remove the beef from the refrigerator and let it sit at room temperature for at least 30 minutes.
While the meat rests, mix the softened butter with the thyme and shallot to make a compound butter. Season the roast with the salt and pepper. Smear the butter all over the tenderloin roast and then put it on a roasting rack over a sheet pan or roasting pan.
Put the roast in the oven and cook until an instant-read thermometer reads 125°F for medium rare (the carryover will be about 7-10°F while the beef rests after searing). This will take about 45 minutes, but after 40 minutes, you should start taking the temperature of the beef. Depending on your oven and how cold the meat was in the center when it went in, it could take up to 60 minutes. Temp it often so that you don’t overcook your beef.
When the meat is at 125° in the center, remove it from the oven. Heat a heavy pan (cast iron works best) on high heat. Add the clarified butter and sear your roast on all sides, about a minute per side MAX. Place the meat on your cutting board and allow it to rest for about 8-10 minutes. Slice and serve with the sauce.

Make the Sauce
While your beef tenderloin is roasting, add the beef stock in a saucepan over medium heat and reduce until you have 2/3 of a cup. This can be done ahead of time. Set aside.
To a saucepan, add the butter over medium heat. Add the shallot and cook, stirring, until the shallot is tender and just starts to brown. Add the wine, peppercorns, and bay leaf. Stir, and cook until there is only about ¼ cup of wine remaining.
Next, strain out the solids and put the liquid back into the pan. Add the vinegar and your reduced beef stock. Stir and cook until thickened. Taste for seasoning – you’ll probably need a little kosher salt here. Remove from the heat and stir in the butter (you can use more if desired). Keep warm until ready to serve but do not boil after the butter is added or your sauce will break.