Preheat oven to 350 degrees Fahrenheit.
In a bowl, mix together flour, salt and pepper.
Cut the onion into strips
Cut the sirloin into thin strips and toss to coat in flour mixture
Heat olive oil in dutch oven on medium and add in onions and coated strips of beef. You will have extra flour, just discard it. Cook the onions and beef on medium until all the beef is browned and you cannot see any white flour, about 7 minutes.
Add beef broth to the pot and stir to get any bits that stuck to the bottom into the liquid. Add in dry pasta.
Add cream cheese and trimmed green beans.
Cover and place in oven for 30 minutes.
Remove cover and continue to cook an additional 30 minutes or until the pasta is al dente and you have a nice gravy.
Allow to cool slightly, serve and enjoy!