In a large bowl mix together ground beef, onion, milk, bread crumbs, egg, Worcestershire sauce, pepper, salts. Form 1 inch round meatballs using a cookie scoop.
In a large skillet heat up butter and cooking oil to a sizzle. Place meatballs in hot skillet in one layer and allow to brown on one side for a few minutes. Flip meatballs over and brown on other side. Roll meatballs until all sides are browned. (NOTE: We are not fully cooking meatballs in this step.) Drain any excess grease.
Add in 2 cups of beef broth and bring to a boil over high heat. Lower heat to a low and place lid on. Cook for 20 minutes. Remove lid and add in uncooked pasta. Mix. (NOTE: not all pasta will be submerged, this is fine.) Place lid back on skillet and cook for 10-12 minutes until pasta is tender. (Give a stir every few minutes and add liquid (extra water or broth) if needed during cooking process.)
Turn off heat and stir in sour cream. Garnish with parsley and enjoy.
These are absolutely amazingly delicious!