01 -
In a 5-quart slow cooker, combine dry onion soup mix, cream of mushroom soup, and beef broth. Whisk together until combined, lumps are acceptable.
02 -
Sprinkle lemon pepper seasoning evenly over the beef cubes and toss to coat.
03 -
Add the seasoned beef cubes to the slow cooker and stir to combine with the liquid mixture. Cover and cook on low for 6 to 8 hours until the beef is tender.
04 -
In a medium saucepan, melt unsalted butter over medium heat. Add flour and whisk continuously until smooth and lightly golden, forming a roux.
05 -
Ladle 2 cups of the slow cooker liquid into the roux, whisking briskly until smooth. Increase heat to medium-high and cook until the gravy thickens.
06 -
Pour the thickened gravy back into the slow cooker, stir to combine, then add the beef cubes back into the gravy. Serve immediately over rice, mashed potatoes, or egg noodles.