Season the beef with salt and pepper and then coat in flour. Place the oil in a large skillet set over medium-high heat. Brown the beef in batches and then add them to your slow cooker along with everything but the green onions. (Mixture will be quite thick, but will thin as the vegetables release their liquid.) Cover and cook on the low setting for 6 to 8 hours until the beef is very tender. Add additional salt and pepper, if needed. Garnish servings of the goulash with sliced green onion.
Note: This recipe is designed for an oval-shaped slow cooker with a 5 litre or more capacity.