Preheat your oven to 350°F (175°C) and prepare a cake pan with parchment or grease.
In a bowl, whisk together flour, baking soda, baking powder, salt, and spices.
In another bowl, mix pumpkin purée, sugars, oil, eggs, vanilla, and sour cream until combined.
Gradually add the dry ingredients to the wet mixture, mixing gently until just incorporated.
Pour the batter into the prepared pan and smooth the top.
Bake until the cake feels springy in the center and soft crumbs appear when tested.
Allow the cake to cool before slicing or frosting.