Salt Hank French Dip Sandwich

1/2 cup fresh rosemary sprigs
1/2 cup fresh thyme sprigs
1/2 cup fresh oregano
1/2 cup fresh sage leaves
2 garlic bulbs (cut in half widthwise), plus 8 peeled cloves, divided
1/2 cup (1 stick) plus 2 tablespoons unsalted butter, divided
1 tablespoon Dijon mustard
2 white onions, sliced in half
2 1/2 pound prime rib roast (2 bone-in ribs)
1 tablespoon flaky salt, plus more for seasoning
1 tablespoon freshly ground black pepper, plus more for seasoning
1 tablespoon extra-virgin olive oil
4 large carrots, peeled and thinly sliced
3 celery stalks, thinly sliced
2 red onions, thinly sliced
3 beef bouillon cubes
8 cups beef stock
1/2 cup plus 2 tablespoons Worcestershire sauce, divided
1 cup Hellmann’s or Best Foods mayonnaise
2 tablespoons prepared horseradish
1/4 cup chopped fresh chives
2 large crusty Italian or sourdough baguettes
Caramelized Onions
12 slices provolone cheese

Preheat the oven to 325ºF.

In a blender, place the leaves of the rosemary, thyme, oregano, and sage. Add the 8 peeled garlic cloves and blend to mince. Add the 1/2 cup (1 stick) of butter cut into cubes and the Dijon mustard. Blend until the butter reaches a soft, whipped consistency and everything is combined.

Place the white onions flat side down on a wire rack− lined roasting dish. Slather the entire roast with the compound butter. Season heavily on all sides with salt and pepper. Place the rib roast on top of the onions, with the top of the roast propped up by the onions and the bottom of the ribs on the wire rack. Roast until the internal temperature of meat reaches 130ºF, about 11/2 hours. Time may vary so make sure to check the temperature periodically. Remove the meat from roasting dish to rest for 30 minutes.

In a large skillet over medium heat, heat the remaining 2 tablespoons of butter and the olive oil. Add the carrots, celery, sliced red onions, the beef bouillon, the remaining 1 tablespoon of salt, and 1 tablespoon of pepper. Cook, stirring occasionally, until the vegetables are softened and caramelized, about 30 minutes. Add the beef stock, 1/2 cup of the Worcestershire sauce, and the halved garlic bulbs. Reduce by 40 percent, about 1 hour. Set the halved garlic bulbs aside, then strain the liquid through a fine-mesh sieve, using a large spoon to push all the liquid out of your solids.

Now take the halved garlic bulbs and pop the softened garlic cloves out of their skins. In a medium bowl, mash the softened garlic cloves with the mayonnaise, prepared horseradish, chives, and the remaining 2 tablespoons of Worcestershire sauce, and season to taste with salt and pepper.

While the meat is resting, lightly toast your baguettes. Using a sharp knife, thinly shave slices of beef from your roast. Slice your baguette in half, and slather your horseradish mayo on the bottom half. On top of that add a large pile of shaved beef, the Caramelized Onions, and slices of provolone. Place both halves under the broiler until the cheese starts to get brown and bubbly. Remove and add more sauce to other half of the bread.

Top your sandwich and cut in half diagonally. Repeat with the remaining baguettes. Serve with hot au jus and enjoy.