This recipe is based on my dad's, which in turn is based on a very old Betty Crocker recipe, I think. I've made a few modifications to suit my own tastes.
The biscuits are just store-bought buttermilk biscuits. Prepare per their instructions.
The recipe for the gravy is as follows.
Ingredients
2 lb. sage ground sausage
5 cups whole milk
8 tbsp butter
¾ cup flour
a generous amount of black pepper
a less generous amount of salt
Instructions
Brown the sausage in a large pan. Remove from heat when done.
Melt the butter in a stock pot.
Whisk the flour into the butter until a roux is formed.
Slowly add the milk to the roux, stirring constantly.
Add the sausage, salt, and pepper. Stir to combine.