For the crust: Beat the butter and brown sugar till creamy. Add the remaining ingredients and mix well.
Press half in a lightly greased 9x13" pan. Bake at 350° for about 8-10 minutes.
While crust is baking, prepare the filling: Grate your apples. Mine were small, so I used three. Stir together all ingredients till well combined. Spread over hot crust.
Top with remaining oatmeal mixture. Bake an additional 40-49 minutes, or till center is set. Cool, then cut into bars. Store in the refrigerator.
Notes
I peeled my apples, but the original recipe called for leaving the skins on.
Leigh Anne used quick oats, but I used regular and thought they were fabulous. So you can use whatever you have.