Preheat the oven to 325℉. Grease a 9X13-inch pan with non-stick cooking spray.

In a large mixing bowl, mix together the oil, brown sugar, eggs, sour cream, pumpkin puree, and vanilla until combined.

In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and spices. Add the dry ingredients to the wet and stir just until no streaks of flour remain.

Pour batter into the prepared pan and smooth the top with a spatula. Bake in the preheated oven for 45-50 minutes or until a toothpick inserted into the center comes out clean. Let cool to room temperature on a wire rack before topping with the frosting.

In a large mixing bowl using an electric handheld mixer, beat the softened cream cheese on high speed for 1 minute. Add the powdered sugar and mix on low speed until incorporated before turning the mixer up to high speed and beating for another 1 minute. Spread the frosting onto the fully cooled cake using an offset spatula.