Preheat the oven to 400℉. 

Fit the pie crust to a 9-inch pie dish.  Crimp the edges and use a fork to poke holes at the bottom.   Place the pie crust in the freezer to chill while you prepare the filling and streusel. 

Combine the tart cherry pie filling and apple pie filling in a large bowl and mix to combine.  Set aside. 

Prepare the streusel.  Add the flour, brown sugar, granulated sugar, pecans, and salt to a bowl and mix with a fork to combine.  Pour the butter over the dry ingredients and continue to mix until the ingredients come together in clumps. 

Assemble the pie.  Pour the cherry-apple filling into the prepared pie crust and sprinkle the streusel on top.  Brush the beaten egg onto the exposed pie crust edges. 

Bake the pie at 400℉ for 25 minutes.  At the 10 minute mark, cover the pie dish with tin foil to prevent the pie crust from over-browning.  After 25 minutes, turn the oven temperature down to 375℉ and continue to bake for 30 minutes.  

While the pie is baking, prepare the whipped cream.  Add the heavy cream, powdered sugar, and pumpkin spice to a large bowl or to the bowl of a stand mixer.  Use a hand mixer or the beater attachment on your stand mixer and beat the ingredients on medium-high speed for 3-5 minutes, until stiff peaks form.  Store the whipped cream in the refrigerator until you are ready to serve.   

Let the pie cool for 2-3 hours, then dollop the pumpkin whipped cream on top, slice, and serve!