Heat a pan over medium high heat (I did this step in my slow cooker because I have a stovetop function). Add in the butter and let it melt. Add in the onions and sauté for 5 minutes. Transfer to the slow cooker.
Stir in the beef. Toss it with the garlic powder, onion powder, pepper, salt and rosemary.
Stir in the water, the onion soup mix and bay leaf.
Cover slow cooker and cook on low for 6 hours or on high for 3-4 hours. Remove the bay leaf.
Stir in the frozen noodles and cook on high with the lid on for another 20-30 minutes.
Stir in the balsamic and sour cream.
Serve and enjoy!
