Creating Thanksgiving Piecaken is straightforward when you follow these steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease and flour two round 9-inch cake pans.

2. Prepare the Pie Filling: In a medium bowl, combine pumpkin puree, sweetened condensed milk, eggs, spices, salt, and vanilla extract. Mix until smooth and well combined.

3. Roll Out Pie Crust: Roll out the pie crust and fit it into a pie dish. Pour the pumpkin filling into the crust, smoothing out the top.

4. Bake Pie: Bake the pie in the preheated oven for about 50 minutes or until the filling is set. Remove the pie from the oven and allow to cool.

5. Prepare the Cake Batter: In a large mixing bowl, cream together softened butter and granulated sugar. Add the eggs, buttermilk, and vanilla extract, mixing until well combined.

6. Combine Dry Ingredients: In another bowl, sift together all-purpose flour, baking powder, and salt. Gradually add the dry ingredients to the wet mixture until just combined.

7. Divide Batter: Evenly divide the cake batter into the prepared cake pans.

8. Bake the Cake: Bake the cake layers for 25-30 minutes, or until a toothpick inserted in the center comes out clean. Let them cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

9. Assemble the Piecaken: Once everything is cool, place one cake layer on a serving platter. Gently top it with the cooled pumpkin pie.

10. Finish with Cake: Place the second cake layer on top of the pie.

11. Optional Toppings: Frost with whipped cream or your favorite frosting, and garnish with pecans, whipped cream, or drizzles of caramel.

By carefully following these steps, you will create a stunning Thanksgiving Piecaken that will astound your guests!