BEAT first 5 ingredients with mixer fitted with paddle attachment on low speed until crumbly. Stop mixer, scrape bowl and paddle. Stir in OREO Pieces just until blended.
SPOON apple pie filling into 2 greased full-hotel pans (or spoon all the pie filling into 1 half-hotel pan for trial recipe). Top with oat topping.
BAKE in 300ºF-convection oven 25 min. or until lightly browned. Serve topped with dulce de leche.