Season your beef liberally with salt and pepper. 

In a large Dutch oven or oven-safe pot, brown all sides of the beef over medium-high heat. Once the meat is browned, move to a to plate to rest while you get everything else ready. Do not clean out the pan. 

Preheat the oven to 325 degrees F (162 C). 

Add beef base and 4 cups of beef broth together in the pot that you used to brown the beef. Add all the spices and herbs. 

Add beef back to the Dutch oven. Make sure the liquid is at least half of the way up the side of the beef. If it is not, add up to one cup of water. 

Roast beef for 2 to 2.5 hours adding more broth or water as needed to keep the liquid at least halfway up the beef. Add more stock or water if needed. 

Remove pot from oven and allow the beef to cool off on a cutting board for at least half an hour. Once the meat is cooled a little, wrap it up or add to a large container and place it in the refrigerator to cool fully. Cool beef for at least 4 hours or overnight. 

Strain the broth into a container and store it in the refrigerator as well. 

When the beef has fully cooled in the refrigerator, remove it and place it on a cutting board. Using a very sharp serrated knife, slice the beef as thinly as possible. Be very careful and patient and shave the meat as thin as you can. 

Prep for 1 sandwich (double or quadruple for multiple sandwiches): In a small pot, bring 3/4 to 1 cup of au jus up to a simmer. 

Add a big handful of sliced beef to the au jus/gravy in the pot. Warm beef in the pot for 3 to 5 minutes until everything is warm. 

Place beef in sliced roll and top with giardiniera or roasted green peppers. 

Dunk the whole sandwich in the au jus if you prefer your sandwich "dipped" or using a spoon scoop and drizzle au jus directly onto the roll.