Preheat oven to 350°F. Spray a 12-cup standard muffin tin with nonstick baking spray.
Add the flour, brown sugar, and walnuts to a medium bowl. Cut the butter into small cubes and then add them to the bowl. Using your fingers or a fork work the butter into the flour and sugar until crumbly.
Open cinnamon rolls and flatten each one with a rolling pin,into 4-inch round (dust with flour if you find it too sticky.)
Place the flattened cinnamon rolls into each muffin tin. Press gently into the muffin tin, and cut off extra around the edges.
Fill each cup with apple pie filing, then top with the crumble topping.
Bake for 15-18 minutes or until golden brown. Top with whipped cream, with ice cream, or drizzle with caramel sauce.