Dice the Yellow Onion (1/2) into medium dice.
In a large cast iron pan over medium heat, melt the Unsalted Butter (2 tablespoon) and begin browning the Country Style Sausage (1 pound). Use a wooden spoon to break the sausage up into smaller pieces.
When almost all the sausage has browned, add the diced onions to the pan. Allow the onions to sweat and cook until the sausage bits begin to brown and crisp up.
When nice and brown, add the All-Purpose Flour (2 tablespoon) and mix it in with the sausage. Cook for a few minutes more, while you cook off the flour.
Add the Milk (2 cup) and stir.
It will take about 7 to 8 minutes for the sausage gravy to thicken. If too thick, add a bit more milk until it is the right consistency. Season with Salt and Pepper (to taste). I like to go heavy on the black pepper.
Serve with biscuits and enjoy!