How to make it:

For beef tips:
Brown the beef tips/stew meat in the InstantPot with the lid off on Sauté until a golden brown crust forms on all sides. Pour in the au jus and dilute according to the package directions. Set to Meat/Stew or Pressure Cook/Manual and set for 35 minutes, making sure the valve is sealed. If using a Crockpot, no need to brown the meat, set to low for 4-6 hours.

For sliced roast beef:
Dump the au jus into a large skillet on medium heat, diluting according to the package directions, add each piece of roast beef in at a time so it's not all in one clump. Cook at a simmer for about 5-7 minutes - no need to mess with it; you're just warming up the beef.

Instructions:
After the meat is cooked, turn your oven broiler on low. Use a nonstick baking sheet, or line one with parchment paper.

Slice your buns. A tip I've learned along the way is to cut a V out of the tops of the buns instead of slicing straight in half. This will help keep the stuffings inside rather than potentially spilling out. 

Build your buns with a slice of provolone cheese and broil for 2-3 minutes, just melting the cheese.

Remove from the oven, pile on some meat, straining most of the juice, then add another layer of cheese on top. Place back in the oven for just a minute to melt the cheese. This is next level goodness.

Ladle a small cup of the juice for dipping, and serve hot.

Enjoy!