Place squirrel legs in buttermilk. Add salt and stir to cover. Marinade for at least 30 minutes, but preferably 8-12 hours.
Mix the flour and seasoning for the fried squirrel breading. Remove squirrel pieces one at a time and place them in the breading. Turn to coat all sides. Repeat until all pieces are coated.
Heat oil and fry each piece for 1-2 minutes on each side. Remove to a paper lined plate to drain.
To make gravy, melt butter in a pan. Add seasoned flour leftover from breading squirrel. Whisk as the flour browns and bubbles, about 1-2 minutes.
Add milk 1/2 cup at a time, stirring constantly. When the gravy thickens, add a bit more milk and continue until you have the desired quantity.
Serve fried squirrel and gravy over your favorite homemade biscuits.