½ cup (115 g) unsalted butter, softened to room temperature
8 ounces (240 g) cream cheese, softened to room temperature
3½ cups (455 g) powdered sugar
1 tsp vanilla extract
½ tsp cinnamon
½ tsp cardamom
¼ tsp nutmeg
¼ tsp ground ginger
¼ tsp ground cloves
¼ tsp allspice
pinch of salt
To make the cake, preheat the oven to 350°F. Line a 9 x 13 inch baking pan with parchment paper and spray. Set aside.
In a medium bowl, whisk together the flour, cinnamon, nutmeg, ginger, baking powder, baking soda, and salt. Set aside.
In a large bowl, whisk together the brown sugar, granulated sugar, eggs, and vanilla until smooth. Add the oil and whisk to combine. Add the buttermilk and whisk to combine. Add the pineapple and carrots and stir with a rubber spatula to combine. Add the flour mixture to the sugar mixture, folding with a rubber spatula until the two are just combined. Fold in the walnuts and raisins.
Pour the batter into the prepared baking pan and smooth out the top with a rubber spatula. Bake the cake for 50 minutes, or until a toothpick inserted into the center comes out clean, the center of the cake is set, and the edges are golden brown. Let the cake cool for 20 minutes in the pan, then invert the cake onto a cooling rack to cool the rest of the way.
To make the chai-cream cheese frosting, combine the butter and cream cheese in a stand mixer fitted with the paddle attachment and beat on medium speed for 2 to 3 minutes, or until the mixture is light and fluffy. Reduce the speed to low and gradually add the powdered sugar. Once the powdered sugar had been incorporated, add the vanilla, cinnamon, cardamom, nutmeg, ginger, cloves, allspice, and salt. Increase the speed to high and beat for 2 minutes.
Place the cake on a serving platter and frost the top of the cake with chai-cream cheese frosting. Cut into squares and serve.
*If you’d like to make this ahead of time, you can make the cake in advance and wrap it tightly in wax paper for up to 2 days. The frosting is best when made right before assembling and serving.