7-8 Granny Smith Apples, peeled, cored and sliced. (about 4 cups)  I like to have it heaping mounded full because the apples bake down and you want a full square pan full.  I buy 9 apples, just incase and that way if I only need 8, I have one to munch on 

1/2 cup Sugar

2 Tablespoons flour  and  1/2 Cup Flour  …  keep separated

1/4 Teaspoon salt

1 teaspoon Cinnamon… plus more

1/2 cup old-fashioned Oats  … NOT the instant stuff

1/2 cup Brown Sugar

1/4 teaspoon each:   baking soda  AND  baking powder

1/4 cup butter

cooking spray…. like Pam

8X8 baking pan

HOW TO:    oven at 350°

spray the baking pan with cooking spray.  set aside.

in a Large bowl, combine apples, sugar, 2 Tablespoons of flour and the cinnamon.  Dump into the baking pan.  Set aside.

in same large bowl, now combine oatmeal, salt, brown sugar, 1/2 cup flour, baking soda and baking powder.  I always add a couple shakes more of cinnamon to this mix as well.  Also crumble up the butter and add it.  I find it easiest to use my hands to combine after adding the butter.

sprinkle the oatmeal mix over the apples.  Very very Lightly press down.  ( I usually use a fork or omit this step.)  I had it once where I pressed the oatmeal mix down and it made a hard thick coating.  It was not a good day.) so go light or not at all.

Bake for about 35 minutes.  use a fork or knife to check apples.  Make sure apples are baked down.  If apples are still a bit crunchy, let them continue baking at 5 minute intervals.