Best Ever Apple Crisp

small apples, peeled and sliced thinly (Gala for a sweeter crisp, Granny Smith for a tarter one)

white sugar

all-purpose flour

ground cinnamon

water (if you like a runnier crisp, you can use up to ½ cup)

quick-cooking oats

flour

packed light brown sugar

baking powder

baking soda

butter, melted