Authors:

You need to either create a slurry in a cold liquid, which also works with cornstarch, or you've got to do your gravy in a very wide pan and kind of scatter the flour over the top and then very quickly whisk it in.

"TV Chef Alton Brown Shares Tips On The Science Of Thanksgiving Dinner". "All Things Considered" with Ari Shapiro, www.npr.org. November 24, 2016.
You need to either create a slurry in a cold liquid, which also works with cornstarch, or you've got to do your gravy in a very wide pan and kind of scatter the flour over the top and then very quickly whisk it in.