4 TLBS butter - melted in a shallow pan
4 TLBS flour - whisked into the melted butter. Continue to cook and whisk until the roux is a light golden color. This will eliminate the raw flour taste and build a deeper more flavorful base for your gravy.
Add the liquid from the crock pot, whisking constantly to incorporate. Add more beef broth, if necessary, to achieve your favorite gravy consistency (not too thick, not too thin - just right).