Melt butter in 12-inch skillet or Dutch oven over medium-high heat. Add pork slices; cook 3 to 5 minutes or until browned on both sides. Remove pork from skillet; set aside.
Reserve 1/4 cup of the broth in 1-cup measuring cup or small bowl. Add remaining broth, Worcestershire sauce, salt, pepper and potatoes to skillet. Bring to a boil. Reduce heat; cover and simmer 13 to 17 minutes or until potatoes are tender.
Reserve 2 tablespoons onions for garnish. Stir remaining onions, mushrooms and pork slices into potatoes. Cover; simmer an additional 5 minutes or until pork is no longer pink in center.
Add flour to reserved broth in measuring cup; blend until smooth. Gradually stir into pork mixture. Cook over medium-high heat for 2 to 3 minutes or until mixture is bubbly and thickened, stirring constantly. Sprinkle with reserved onions.