Preheat the oven to 365°F (185°C). Grease and flour a 9x13-inch pan, or line it with parchment.

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

In a large bowl, whisk the oil, melted butter, eggs, and granulated sugar until smooth and well combined. Whisk in the pumpkin purée and vanilla.

Add the dry ingredients to the wet and fold with a spatula until just combined. Don’t overmix.

Pour the batter into the prepared pan and smooth the top. Bake for exactly 25 minutes, or until a toothpick inserted in the center comes out clean or with a few loose crumbs.

Cool the cake completely in the pan before frosting. Frosting a warm cake will make it melt and slide.

Beat the softened butter and confectioners’ sugar together until smooth and fluffy. Mixing the sugar with the butter first coats it in fat, which makes it harder for the sugar to pull moisture out of the cream cheese.

Once the butter and sugar are well mixed, add the cream cheese and beat until just combined. The cream cheese stays intact and doesn’t turn runny or weepy.

Beat in the vanilla and salt. Spread over the cooled cake.