Prep: Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.

Combine Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, salt, pumpkin pie spice, and cinnamon. Set aside.

Mix Wet Ingredients: In a large bowl, whisk the granulated sugar, brown sugar, and oil together until combined. Add the eggs one at a time, whisking well after each addition. Mix in the vanilla extract and pumpkin puree until smooth.

Combine Everything: Gradually add the dry ingredients to the wet ingredients in three parts, alternating with the buttermilk in two parts, beginning and ending with the dry ingredients. Gently fold with a spatula after each addition until just combined; do not overmix.

Bake: Divide the batter evenly between the 12 cupcake liners, filling each about ⅔ full. Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.

Cool: Allow the cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely before frosting.

Make Frosting: While cupcakes cool, beat the softened butter and cream cheese together with an electric mixer on medium speed until smooth and creamy. Beat in the salt. Gradually add the sifted confectioners’ sugar, one cup at a time, on low speed until incorporated. Increase speed to high and beat for 2 minutes. Add the vanilla extract and beat until combined and fluffy.

Frost: Once cupcakes are completely cool, frost with a knife or pipe the cream cheese frosting onto the flat tops.