Preheat oven to 375°F. Line a cookie sheet with parchment paper or a silicone baking mat.
Unroll the pizza crust into a long rectangle. Leave 1" at either and and cover with a layer of roast beef and a layer of cheese.
Decide how many rolls you want. For 8-10 rolls, roll up using the short end. For 12-16 rolls, roll up starting with the long side. Pinch the end to seal. Slice into equal size rolls and place on cookie sheet. Bake for 15-22 minutes, depending on size, until the dough is cooked through.
While the rolls are baking, make the au jus. Heat oil in a medium saucepan over medium heat. Add onion and cook about 3-4 minutes, until semi-translucent, then add the garlic and cook 1 minute more. Add the beef stock, Worcestershire, soy sauce, and bullion cubes, if using. Bring to a boil and cook for 4-5 minutes boiling (or until the bullion is dissolved). Taste carefully, and add salt and pepper as desired.
Serve hot rolls with the au jus.