Preheat the oven to 350°F (175°C). Grease a Bundt pan.
In a bowl, whisk together flour, baking powder, baking soda, salt, and pumpkin pie spice.
In a large bowl, beat the butter and sugar until fluffy. Add eggs one at a time, mixing well.
Stir in pumpkin puree and vanilla extract.
Alternately add the flour mixture and buttermilk to the wet ingredients, mixing until combined.
Pour the batter into the prepared Bundt pan and smooth the top.
Bake for 50-55 minutes, or until a toothpick inserted in the center comes out clean.
Cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
Drizzle with your favorite glaze or dust with powdered sugar before serving.