Add onions to drippings in Skillet
; cook and stir 5 min. or until crisp-tender. Stir in flour; cook and stir 1 min. Add 1 cup broth; cook and stir 2 min. or until sauce comes to boil and thickens. Pour into Slow Cooker
. Stir in remaining broth. Add potatoes; cover with lid. Cook on LOW 4 to 5 hours (or HIGH 2 to 3 hours).