Preheat the oven to 350°F (175°C). Grease and flour the loaf pan or line it with parchment paper for easier removal.
In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger. Set aside.
In a large mixing bowl, beat the softened butter and granulated sugar with an electric mixer on medium speed until light and fluffy, about 3-4 minutes.
Add the eggs to the butter and sugar mixture, one at a time, mixing well after each addition.
Stir in the pumpkin purée, buttermilk, and vanilla extract until combined.
Gradually incorporate the dry ingredients into the wet ingredients, mixing until just combined. Do not overmix.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake in the preheated oven for about 60 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove from the oven and let the pound cake cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.