1 Combine The Buttermilk (Or Yogurt And Milk) With 1 1/2 Teaspoons Salt And 1 Teaspoon Black Pepper In A Large Bowl. Add The Onions To The Buttermilk Mixture And Coat Thoroughly. Let Sit At Least 15 Minutes. 2 In A Separate Bowl Combine The Flour And Cornmeal, 1 Teaspoon Of Salt And 1/2 Teaspoon Of Pepper. Set Aside. 3 Add The Oil To A Largish Dutch Oven Pan - About 5-Quart Or 6 Quart Size. Make Sure That The Pan Is Absolutely Dry Inside Before You Add The Oil. Any Water Droplets In The Pan Will Cause The Oil To Splatter Violently As It Heats Up. The Oil Should Create A Layer Anywhere From 3/4-Inch To An Inch Thick. Use More Oil If Necessary. Heat The Oil To 350