Pumpkin Spice Cake Scratch Recipe. Mix in the sour cream, then the pumpkin puree on a low speed. With a small mixing bowl and a whisk, blend together the cake flour, baking powder, pumpkin pie spice, and salt.

Scrape the sides and bottom of the bowl. In a large bowl, whisk together pumpkin, brown sugar, granulated sugar, sour cream, oil, eggs, melted butter, and vanilla bean paste.