Preheat oven to 375°.
Coat a 9-inch cast-iron skillet with cooking spray. Place in a 375° oven for 10 minutes.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 4 ingredients (flour through salt) in a large bowl. Combine crawfish and remaining ingredients in a medium bowl; stir well with a whisk. Add to flour mixture, stirring until moist. Pour batter into preheated pan. Bake at 375° for 35 minutes or until a wooden pick inserted in center comes out clean.