Steps
- Preheat the oven to 350°F / 175°C. Grease a 9 × 13in / 23 × 33cm baking pan.
- Whisk 2 cups of all-purpose flour, 2 teaspoons of baking powder, 1 teaspoon of baking soda, 1 teaspoon of salt, 1½ teaspoons of ground cinnamon, and 2 teaspoons of pumpkin pie spice together.
- In another bowl, whisk 1 cup of vegetable oil, 4 large eggs, 1 cup of packed light brown sugar, ½ cup of granulated sugar, 425g of canned pumpkin puree, and 1½ teaspoons of vanilla extract. Whisk into the dry ingredients until combined.
- Spread in the pan and bake for 30-36 minutes, until a toothpick inserted in the center comes out clean. Loosely cover with foil if browning too quickly, then cool completely in the pan on a rack.
- Beat 226g of softened full-fat brick cream cheese with ½ cup of softened unsalted butter until smooth. Add 3 cups of confectioners' sugar, 1 teaspoon of vanilla extract, and ⅛ teaspoon of salt.
- Beat on low for 30 seconds, then on high for 2 minutes. Spread over the cooled cake and refrigerate for 30 minutes before slicing.