Preheat oven to 400 degree F. Lightly coat six 6-ounce individual quiche dishes with nonstick cooking spray. Arrange in a 15x10x1-inch baking pan; set aside. In a medium bowl, combine eggs, granulated sugar, vanilla, and salt; whisk until light and frothy. Whisk in milk until combined. Add flour and baking powder; whisk until smooth.