This is a half size version of a cake recipe for a 9 x 12 pan.
(Double all quantities if you are baking in a larger pan)
1 cups all-purpose flour
1 teaspoons ground cinnamon
3/4 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1/8 teaspoon ground cloves
⅛ teaspoon ground ginger
1/4 teaspoon ground nutmeg
1/4 teaspoon ground allspice
1/2 cup unsalted butter, softened
1/2 cup firmly packed dark brown sugar
1/4 cup white sugar
2 large eggs, at room temperature
1/2 teaspoon vanilla extract
3/4 cups buttermilk, at room temperature
Cream Cheese Frosting:
1/4 cup unsalted butter, at room temperature
4 ounce) package cream cheese, at room temperature
1 1/4 cups confectioners' sugar
1/2 teaspoon vanilla extract
pinch of salt
1 tablespoons heavy cream
Directions
Preheat the oven to 350 degrees F (175 degrees C). Grease an 8-inch square baking pan.
Whisk together flour, cinnamon, baking powder, baking soda, salt, cloves, nutmeg, ginger and allspice in a bowl until well combined.
Cream together butter, brown sugar, and white sugar in a large bowl with an electric mixer until light and fluffy. Beat in eggs, 1 at a time, mixing well after each addition. Mix in vanilla extract. Add in half of the flour mixture, and stir until just combined. Pour in buttermilk, and mix until just combined. Add in remaining flour mixture and mix until just combined. Pour batter into the prepared pan and spread into an even layer.
Bake in the preheated oven until the middle of the cake springs back lightly when touched, 35 minutes (add 10-15 minutes if doubled). Remove from the oven and allow the cake to cool completely before frosting
For the frosting, cream butter in a large bowl until smooth. Add cream cheese and beat until thoroughly combined. Mix in confectioners' sugar, 1 cup at a time, and beat until smooth after each addition. Mix in vanilla and salt. Add in heavy cream and beat until frosting is smooth, about 2 minutes. Frost cooled cake as desired.
https://www.allrecipes.com/recipe/286259/kims-buttermilk-spice-cake/