Brown the sausage in a large cast-iron pan, chopping into small pieces as you go. Try to cook it long enough to get some actual browning on the meat
Remove sausage from pan, leaving fat and any stuck-on crispy bits behind. Add and melt enough butter to make 4tbsp of fat
Add 4tbsp of flour. Stir until butter and flour are mixed thoroughly and allow to cook for 1 minute
Slowly stir in preheated milk, an ounce or two at a time, stirring constantly and making sure each addition is fully absorbed before continuing
Once all milk has been added, return the sausage to the pan and stir into the gravy.
Cook until the gravy thickens to your desired texture. Serve over biscuits with hot sauce