2 pounds ground beef (80/20 or similar)
1.5 ounces dry onion soup mix (1 packet)
2 (10.5-ounce) cans condensed cream of mushroom soup
1 cup water
In a large bowl, combine the ground beef and dry onion soup mix. Use clean hands to gently work the seasoning through the meat until it’s evenly distributed, being careful not to overmix so the patties stay tender.
Divide the seasoned beef into 6–8 equal portions, depending on how large you’d like the patties. Shape each portion into an oval, about 3/4 inch thick, pressing the centers just slightly so they cook evenly and resemble little steaks.
If you have a few extra minutes and want deeper flavor, lightly brown the patties in a skillet over medium-high heat, 2–3 minutes per side, just until they get some golden color. This step is optional but adds those nice seared edges like my grandma used to do on her old cast-iron pan.
Lightly grease the bottom of your slow cooker crock. Arrange the beef patties in a single layer, overlapping just a bit if needed but keeping them mostly in one even layer so they cook uniformly and stay submerged in the gravy.
In a separate bowl, whisk together the condensed cream of mushroom soup and the water until smooth and combined. The mixture will be thick but pourable; this is your gravy base that will bubble up around the patties as they cook.
Pour the soup mixture evenly over the patties in the slow cooker, making sure each one is coated and that the gravy runs down between them. Use a spatula or spoon to nudge the sauce around so there are no dry spots showing.
Cover the slow cooker with the lid and cook on LOW for 6–8 hours or on HIGH for 3–4 hours, until the patties are cooked through, very tender, and the gravy is thick, glossy, and gently bubbling around the edges.