Lightly coat the bottom and sides of your slow cooker with nonstick cooking spray.
Add the beef stew meat and baby potatoes to the slow cooker.
Sprinkle the onion soup mix, garlic powder, sea salt, and black pepper evenly over the beef and potatoes.
Add the minced garlic and gently toss everything together to distribute the seasonings.
Cut the butter into smaller pieces and arrange them over the beef and potatoes.
Pour the water or beef broth around the ingredients.
Cover and cook on HIGH for 3–4 hours or LOW for 6–8 hours, until the beef is tender and the potatoes can easily be pierced with a fork.
Add the trimmed green beans during the final 1–2 hours of cooking. For firmer green beans, add them closer to the end.
Gently stir the Slow Cooker Garlic Butter Beef Bites and Potatoes before serving so the beef, vegetables, and savory butter mixture are well combined.
Taste and adjust the salt and black pepper as needed, then serve warm.