Rinse the roast under cold water, pat dry with paper towels, and place on a cutting board. Following the line of the bones, cut the meat away from the bones in 1 piece. Season the meat and the bones all over with the salt and pepper. Rub the meat and bones all over with the garlic.
Fit the meat back onto the bones, making sure to match the meat and bones up where they were cut apart, and tie together between each bone with butcher’s twine. Place the roast on a large plate or baking sheet and refrigerate uncovered overnight.
Remove the roast from the refrigerator and let it sit at room temperature for 30 minutes to 1 hour. Meanwhile, heat the oven to 200°F and arrange a rack in the lower third.
Place the roast fat-side up (the bones will be on the bottom) on a roasting rack set in a roasting pan. Roast until the center reaches 120°F on an instant-read thermometer, about 4 to 6 hours. Meanwhile, make the jus.
For the jus:
Set a fine-mesh strainer over a medium saucepan; set aside. Season the beef bones with salt and pepper.
Heat the oil in a Dutch oven or large, heavy-bottomed pot with a tightfitting lid over medium-high heat until shimmering. Add half of the bones and sear until golden brown on all sides, adjusting the heat as needed so the bottom of the pan does not burn, about 6 to 8 minutes total. Remove the bones to a large plate and repeat with the remaining bones.
Add the wine and simmer, scraping up any browned bits from the bottom of the pan with a wooden spoon, until the wine is reduced by half, about 3 to 4 minutes.
Return the bones and any accumulated juices to the pot. Add the beef broth, measured salt, and measured pepper and bring to a boil. Reduce the heat to low, cover, and simmer until the jus is deeply flavored, about 15 minutes. Uncover, increase the heat to medium, and simmer until the liquid is reduced to about 2 1/2 cups, about 10 minutes.
Remove and discard the bones. Pour the jus through the strainer and discard the contents of the strainer. Let the jus sit until the fat rises to the surface, about 5 minutes. Using a spoon, skim off and discard the fat. Taste and season with salt and pepper as needed. Cool to room temperature and refrigerate tightly covered until ready to serve. To reheat, bring to a simmer over medium heat.
For the horseradish cream:
Place heavy cream in a medium bowl and whisk until the cream starts to hold a line when you drag the whisk through it. Using a rubber spatula, fold in crème fraîche or sour cream, horseradish, chives, and salt. Season with pepper and additional salt as desired.
To finish roasting the meat:
Place the roasting pan on a wire rack, tent the roast loosely with foil, and set aside in a warm place for at least 30 minutes or up to 1 hour. Meanwhile, increase the oven temperature to 450°F and keep the rack in the lower third.
When the roast is done resting, remove the foil and crumple it into a ball. Place the ball of foil under the bones of the roast to prop up the less exposed area of fat. Roast until a dark brown crust forms over the entire top surface, about 8 to 10 minutes. Remove the roast to a cutting board. Cut, remove, and discard the twine. Slice and serve immediately with the jus.