Preheat your oven to 350°F and line a 9x13-inch baking pan with parchment paper. Leave edges hanging over the sides for easy removal after baking and cooling completely.

Whisk together flour, baking powder, salt, and pumpkin pie spice in a medium bowl until combined. Set this dry mixture aside while you prepare the wet ingredients separately.

Beat softened butter and granulated sugar together for 2-3 minutes until light and fluffy. Add eggs one at a time, then vanilla extract, beating after each addition until well incorporated.

Fold the pumpkin puree gently into the butter mixture until just combined. Now fold in the dry ingredients in two additions, being careful not to overmix the batter, which can make the bars dense and tough.

Spread half the pumpkin cake batter evenly into the prepared pan. This base layer prevents the cream cheese from sinking to the bottom during baking.

Beat cream cheese, powdered sugar, heavy cream, and cinnamon for 2-3 minutes until smooth and spreadable. Dollop this cream cheese mixture over the batter base, then top with remaining pumpkin cream cheese bars batter in small spoonfuls.

Using a knife or skewer, swirl through the layers with gentle figure-eight motions to create marble patterns. Bake for 32-37 minutes until a toothpick inserted in the center comes out with just a few moist crumbs.

Cool completely in the pan for at least 2 hours before cutting into 16 squares. Lift the entire block out using the parchment edges, then slice with a sharp knife cleaned between cuts.