Brown the sausage in a large pan over medium heat until cooked through, stirring often to break up the meat into crumbles.
Add the flour, sage, salt, thyme, black pepper and nutmeg; cook for about a minute, stirring often.
Pour in the milk and stir well. Bring to a simmer, stirring often, and cook until gravy thickens to your liking. If needed, add a bit more salt to taste.
Serve hot over (split) biscuits. Top with another grinding of black pepper if you desire.