In a large mixing bowl, mix the 2 cups granulated sugar, 1 3/4 cups all-purpose flour 3/4 cup unsweetened cocoa powder, 1 teaspoon baking powder, 1 teaspoon baking soda, 1/2 teaspoon kosher salt, 2 large eggs, 1 cup milk, 1/2 cup vegetable oil, 1 tablespoon vanilla extract, and 1 cup water.
Mix well until smooth.
Spray your cake pan with non-sticking spray.
Pour the batter into the prepared pan, filling about 2/3 way full. Depending on the size of your pan and air fryer, you can fill two cake pans.
Set into the air fryer for 12-15 minutes at 320 degrees F, air fryer setting.
Stick a toothpick into the center of the cake. If it comes out clean, remove the cake; otherwise, continue to air fry until completely baked through.
In a large mixing bowl, mix together the 3 cups powdered sugar, 2/3 cup unsweetened cocoa powder, 1/2 cup butter, and 8 tablespoons milk Mix until creamy.
Let cool before frosting.