Place cold butter, all purpose flour, quick cooking oats and brown sugar in a medium sized bowl. Use a pastry blender or two forks to cut the butter into the rest of the ingredients. When done, the butter should be about the size of peas. Set streusel topping aside until ready to use.
Place the prepared pizza dough (enough for a single pizza) onto a lightly floured work surface. Roll the pizza dough out into a 12" circle. Fold the dough over in half, and transfer it onto a pizza stone, pizza pan or a large baking sheet. Unfold the dough.
Evenly spread the apple pie filling over the dough, leaving about an inch border around the edges bare. Evenly distribute the streusel topping over the apple pie filling, leaving the border around the edge bare.
Place the apple pie dessert pizza into a preheated 400°F oven, on the middle rack. Bake for about 20 minutes. Oven temps vary, so check it at about 18 minutes. When done, the streusel topping should be golden brown, the filling will be bubbling, and the bottom crust will be light golden brown, as well. Transfer the pizza to a wire rack or cutting board to cool completely.
While pizza cools, make the icing, by mixing together the powdered sugar, apple juice (or water), cinnamon and vanilla until smooth. NOTE: Do not drizzle pizza with the icing until pizza has completely cooled. Drizzle the icing decoratively over the top of pizza. Let the icing harden before slicing and serving the apple pie dessert pizza! Enjoy!
NOTE: The caloric calculation for this dessert was made based on the use of a 13.8 ounce container (in the tube) of Pillsbury pizza dough for the crust. I used homemade pizza dough to make this dessert, as I acknowledge that a lot of people will use store bought pizza dough. Your calorie count will vary, based on the ingredients in the dough used.
Apple Pie Dessert Pizza https://www.thegratefulgirlcooks.com/apple-pie-dessert-pizza/