How to make Jus without a Roast

Usually a jus is made at the last minute, when the roast is done. This is fine if you’re making roast chicken for four people, but it’s a hassle if you’re cooking for a crowd. In my restaurant, we used the jus from the roast chicken from the night before and saved the fresh jus for the next day, but this isn’t practical at home. Cooks sometimes try to make jus by using a concentrated broth, but broth has a different character than a jus and, even when sign