Place the beef and halved potatoes in the slow cooker.
In a small bowl, whisk together melted butter, garlic, Italian seasoning, onion powder, salt, and pepper.
Pour the butter mixture over the beef and potatoes and toss to coat evenly.
Cover and cook on low for 6–8 hours or on high for 4 hours, until the beef is tender and potatoes are cooked through.
Stir gently before serving and garnish with fresh parsley.