Heat a medium sauce pan over low heat, warm milk on low, stir occasionally – keep an eye on it so it doesn’t boil

In a large skillet (good to use cast iron if you have it) heat bacon grease over medium high heat – add sausage

Crumble & cook until well browned and no longer pink

Sprinkle flour over sausage & cook, stirring for 1-2 minutes

Add warm milk all at once, cook – stirring, until it is thickened and bubbly

Turn heat all the way down, add sage, season with salt & pepper

Continue stirring & tasting until the flavor it to your liking

Turn off heat

Gravy will thicken as it cools – serve over warm biscuits