Remove the beef from the refrigerator 30 minutes before cooking to bring it to room temperature.

Pat the roast dry with paper towels and season all over with 2 tablespoons kosher salt and 1 tablespoon freshly ground black pepper.

Heat 2 tablespoons olive oil in a heavy-bottomed roasting pan or Dutch oven over medium-high heat until shimmering.

Sear the beef roast on all sides, about 2 to 3 minutes per side, until deeply browned.

Remove the roast and add 1 medium chopped onion, cooking for 4 minutes until golden, then add 3 cloves minced garlic and cook for 30 seconds.

Pour in 1 cup beef broth and 1/2 cup water, scraping up browned bits, then return the roast to the pan and add 2 sprigs fresh rosemary and 2 sprigs fresh thyme.

Cover the pan with a lid or foil and roast in a preheated 325°F oven for 1 hour 15 minutes or until the internal temperature reaches 135°F for medium-rare.

Transfer the roast to a cutting board, tent with foil, and rest for 10 minutes while you strain the pan drippings into a small saucepan.

Slice the beef against the grain into thin slices about 1/4 inch thick; brush slider buns with 3 tablespoons butter and toast cut-side up at 375°F for 3 to 4 minutes until golden.

Warm the sliced beef and pan drippings over low heat until heated through, then assemble sliders with beef, cheese, arugula, mustard, horseradish sauce, red onion, and pickle slices as desired.