• Preheat the oven to 350°F and grease a 9x9 baking pan with cooking spray or vegan butter. Or, line the bottom with parchment paper.

Batter

• In a mixing bowl, combine the vegan buttermilk, brown sugar, granulated sugar, pumpkin purée, oil, and vanilla. Whisk everything together until smooth.
• Sift the flour, baking soda, baking powder, salt, cinnamon, and pumpkin pie spice into the bowl of wet ingredients. Gently fold the dry ingredients into the wet ingredients with a spatula until no flour streaks remain. Be careful not to overmix.

Bake

• Transfer the batter to the prepared baking pan, making sure to spread it out evenly with a spatula.
• Bake for 25-30 minutes, or until the center is springy when gently pressed and a toothpick inserted into the center comes out clean or with a few crumbs attached.
• Remove the bars from the oven, set the pan on a wire rack, and let them cool in the pan for about 45-60 minutes. You can also chill them in the fridge to speed up the process.

Frosting

• With a hand mixer or stand mixer, beat the vegan butter and cream cheese until smooth and creamy, then add the vanilla, pumpkin pie spice, and powdered sugar. Beat on low until the sugar is incorporated, then switch to high for another 1-2 minutes to achieve a light and creamy texture.

Assembly

• When the bars have cooled, add the frosting on top and spread it out evenly. To help firm up the frosting, chill the bars in the fridge for another 30-60 minutes before slicing and serving. You can garnish them with extra pumpkin spice or cinnamon sugar if you’d like. Happy eating!