Preheat oven to 350F (176C) and prepare a baking pan (we used a 9" x 13" rectangular pan) by greasing the sides and lining the pan with parchment paper.
Mix together your wet ingredients (pumpkin puree, vegetable oil, eggs, vanilla extract, brown sugar, and granulated sugar) in a mixing bowl. Whisk well to combine.
In a separate bowl, mix together your dry ingredients (flour, baking powder, baking soda, pumpkin pie spice, cinnamon, and salt). Whisk well to combine.
Combine the wet and dry ingredients by whisking together until the mixture is just hydrated - don't overmix!
Transfer the batter to the prepared baking dish. Spread into an even layer.
Bake the cake for 30-40 minutes until a cake tester inserted in the middle of the cake comes out clean.
Let the cake cool completely. In the meantime, prepare the cream cheese filling. Add butter to the bowl of a stand mixer and whip until it becomes lighter in color and texture.
Add in the powdered sugar, a pinch of salt, and orange zest. Continue to whip this until it's a light and fluffy consistency.
Add the cream cheese in two batches, mixing until well-combined, and this should give you a smooth, lump-free cream cheese frosting.
When the cake has cooled, spread cream cheese frosting across the top. Add any additional decoration, such as candied orange slices, orange sprinkles, or orange zest. Slice and enjoy!