In a bowl, combine the buttermilk, Mesquite seasoning and egg. Whisk well.
In a separate bowl, combine the flour, Original seasoning, baking powder and cornstarch.
In a Dutch oven, pour in enough oil to deep-fry the steaks (2 to 3 inches). Heat the oil over medium-high heat until it reaches about 350°F.
Pick up one piece of meat and dip it into the wet batter and then into the flour mixture. Be sure both sides are well coated. Repeat, or as I call it, “double baptize.”
Fry the steaks for about 3 to 4 minutes on each side, or until golden brown. Be sure there is no red liquid coming from the steaks. Cool on a wire rack. Serve warm with the gravy.