chasinghosts : I have never heard of thickening gravy with flour & ( butter ). I have heard of flour & water . But most people when I was growing up used corn starch & water . My parents both used cornstarch & water . But I'll have to try this .
@bbk : I use Wondra and water or milk for lighter colored gravy. If I'm out of water I use flour, but you have to mix either one in with the liquid really well and stir with a whisk to keep from lumping.