In a quart slow cooker, add potatoes and asparagus to opposite ends of the slow cooker. Mix the onions and steak together. Then, place them in the center.
In a medium bowl, add melted butter, garlic, Worcestershire sauce, black pepper, paprika, mustard powder, rosemary, and thyme. Whisk until well combined and pour over everything.
Cover and cook on low for 4-5 hours.
Serve while hot, and enjoy!
