Preheat the oven to 350°F and set aside a greased half-sheet cake pan.
In a large bowl, whisk together all ingredients until thoroughly combined. Transfer batter to prepared pan and bake until lightly browned and an inserted toothpick comes out clean, about 30 to 35 minutes. Remove from the oven and cool completely.
Prepare Frosting and Assemble
In a large bowl, whisk together all ingredients until thoroughly combined. Spread frosting over the top of the cooled cake in an even layer. Garnish with desired fruits and refrigerate until ready to serve.