Rinse and dry squash using a paper towel, then slice them into ⅛-¼ inch slices. Try to make even slices, so they cook in the same amount of time.
Whisk the milk and egg in a shallow bowl, and set aside. In a second shallow bowl, combine all dry ingredients—flour, cornmeal, salt, pepper, and Creole seasoning. Mix well.
Dredge the squash slices in the buttermilk and egg mixture, then in the cornmeal mixture, ensuring they are completely coated. Shake off excess cornmeal mixture from the squash, then arrange them in a single layer on a baking sheet while you get them all done. Let the squash sit for about 2-3 minutes, which will help the cornmeal mixture stick to the squash.
Heat about half an inch of oil over medium-high heat in a large deep skillet.
When the oil is hot (the oil will immediately form bubbles around a wooden spoon when dipped into it), place the squash in the oil using tongs. Fry the squash in small batches until golden brown and crisp—about 4-5 minutes, flipping halfway in the frying process to ensure even cooking on both sides.
Transfer fried squash to a paper towel-lined plate to soak off excess oil. Cool for 1-2 minutes, then serve with your favorite sauce.