Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking pan or line it with parchment paper.
In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, and cloves until well combined.
In a large bowl, mix brown sugar, granulated sugar, vegetable oil, and melted butter until smooth.
Add pumpkin puree to the sugar mixture and stir until fully incorporated.
Beat in the eggs one at a time, mixing well after each addition.
Stir in the buttermilk (or yogurt) and vanilla extract.
Gradually fold the dry ingredients into the wet ingredients, mixing gently until just combined. Do not over mix.
If using nuts, gently fold them into the batter.
Pour the batter into the prepared baking pan and smooth the top evenly.
Bake for 30–35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Allow the cake to cool in the pan for 10–15 minutes before slicing or frosting.