Pat the roast dry and season generously with salt & pepper.

Heat 1 1/2 tbsp tallow in a Dutch oven over medium-high heat. Sear roast on all sides, about 10-12 minutes total. Work in batches if needed.

Add the remaining tallow & onions. Cook for 12-15 minutes until deeply browned. Add garlic and tomato paste & cook for 1 minute.

Pour in the Cabernet, scrape up the browned bits, & simmer until reduced by half.

Add beef broth, beef base, Worcestershire, soy sauce, balsamic, thyme, & bay leaves. The liquid should come about halfway up the roast.

Cover and braise at 300°F for 3-3 1/2 hours, until fork-tender.

Remove the beef and let it rest for 15-20 minutes. Strain the jus and simmer for 10-15 minutes to concentrate the flavor.

Mix all horseradish mayo ingredients together.

Thinly slice the beef against the grain or shred it, then warm it in the jus.

Spread horseradish mayo on the rolls, add provolone, and toast at 350°F for about 5 minutes until melted. Pile on the beef, add more cheese, & broil until bubbly.

Serve with a bowl of hot au jus for dipping!