Heat the oven to 350°F. Slice the top from the garlic bulb, drizzle the exposed cloves with 1 teaspoon olive oil, wrap the bulb in foil, and roast for 30–40 minutes, until the cloves are soft; cool slightly.

Squeeze the softened garlic from the skins and mash it. Stir the roasted garlic together with 2 tablespoons olive oil, rosemary, thyme, kosher salt, and black pepper to form a spreadable paste.

Pat the rib roast dry with paper towels. Rub the garlic-herb paste thoroughly over every exposed surface, then let the roast stand at room temperature for about 45–60 minutes before cooking.

Place the roast bone-side down in a roasting pan. Roast at 450°F for 15–20 minutes to brown the exterior, then reduce the oven temperature to 325°F without removing the roast.

Continue roasting until an instant-read thermometer inserted into the thickest part reaches approximately 120–125°F for rare to medium-rare or 130–135°F for medium. Begin checking according to the shape and size of the roast rather than depending only on the clock.

Transfer the roast to a cutting board and tent it loosely with foil. Rest for 20–30 minutes so the juices redistribute and the internal temperature rises several degrees, usually by 5–10°F.

Slice between the bones for generous bone-in servings, or remove the bones first and slice the roast across the grain. Serve the slices while warm with the browned garlic-herb crust facing upward.