No, brown gravy is technically not the same as au jus. If you don’t have au jus or prefer to make your own seasoning blends (like I do), you can substitute 2 Tbsp granulated onion and 2 Tbsp cornstarch for the au jus packet. If you're feeling fancy, you can use a packet of dry onions soup mixes, or you can make your own dry onion soup mix.