In a large bowl, stir together cinnamon, brown sugar and flour.
Using a food processor, crumble to gingersnap cookies until they are small pea-sized pieces.
Add cookie crumble and the pieces of cold butter into the bowl. Using a pastry blender (or fork), mix the butter into the mixture until it is a crumbly texture. Be careful not to over mix.
Sprinkle over the pie filling of your choice. Follow the baking instructions of your pie recipe. Enjoy!