Creating the Pumpkin Spice Latte Ice Cream Cake can be straightforward if you follow these simple steps:

1. Preheat: Begin by preheating your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
2. Mix Dry Ingredients: In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, baking soda, salt, and pumpkin pie spice.
3. Cream Butter: In another bowl, cream the softened butter until light and fluffy. You can use a hand mixer or stand mixer for this step.
4. Add Eggs: Beat in the eggs, one at a time, until thoroughly incorporated.
5. Add Pumpkin: Stir in the pumpkin puree and vanilla extract, mixing well.
6. Combine: Gradually add the dry mixture to the wet mixture, alternating with the buttermilk. Mix until just combined; do not overmix.
7. Divide Batter: Pour the batter evenly into the prepared cake pans and smooth the tops.
8. Bake: Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
9. Cool Cakes: Remove the cakes from the oven and allow them to cool in the pans for 10 minutes. Turn them out onto wire racks to cool completely.
10. Freeze Ice Cream: While cakes are cooling, take the pumpkin ice cream out to soften slightly for easier spreading.
11. Assemble Cake: Once the cakes are cool, place one layer on a serving platter. Spread a thick layer of softened pumpkin ice cream on top. Then, carefully add the second cake layer on top of the ice cream layer.
12. Freeze: Place the assembled cake in the freezer for at least 1 hour to set.
13. Topping: After setting, remove the cake from the freezer and top with whipped cream. Sprinkle with pumpkin pie spice or drizzle caramel sauce if desired.
14. Slice and Serve: To serve, cut into generous slices and enjoy this marvelous dessert!