Toss beef patties and mushrooms into the slow cooker with the gravy mix for a meal that’s so good, it tastes just like a classic diner favorite.

Step 1: Make the Patties
In a large bowl, combine the ground beef, breadcrumbs, milk, onion soup mix, and thyme. Mix gently with your hands until just combined. Shape the mixture into 8 equal, oval patties.

Step 2: Prep the Slow Cooker
Arrange the sliced onions in the bottom of the slow cooker. This acts as a base for the patties and infuses the gravy with sweet onion flavor.

Step 3: Sear the Patties
Heat the olive oil in a skillet over medium-high heat. Lightly coat each patty in flour, shaking off any excess. Brown the patties for about 3–4 minutes per side.

Step 4: Layer and Add Gravy
Place the browned patties on top of the onions in the slow cooker. In a bowl, whisk together the condensed soup, water, and au jus mix. Pour the mixture over the patties.

Step 5: Slow Cook
Cover and cook on Low for 4–5 hours. The patties will become tender, and the onions will melt into the savory, flavorful gravy.