Preheat oven to 350F. Butter and line with parchment paper a 9x13" baking pan.

In a bowl, whisk together the cake flour, baking powder, baking soda, and salt. Set aside.

In the bowl of a stand mixer fitted with the whisk attachment, combine the sugar, softened butter, and olive oil. Mix on LOW speed until incorporated then beat on HIGH speed for 2 to 3 minutes, until very light and fluffy.

On Medium speed, add the eggs one at a time until incorporated. Beat 2 more minutes.

Add the buttermilk, sour cream, vanilla, and almond extract. Mix until smooth, but it's okay if it looks curdle-like.

Add the flour mixture and mix just until combined. Use a rubber spatula to help finish folding in the flour to prevent any over mixing (which causes dense cake).

Transfer the cake batter to the prepared pan. Evenly spread out the top with a rubber spatula.

Bake on the middle rack for 25 to 30 minutes, until a toothpick inserted into the center comes out clean or with just a few moist crumbs.

Let cool in the pan for 20 minutes then transfer to a wire rack to cool completely.

Combine the softened cream cheese and butter in the bowl of a stand mixer fitted with the paddle attachment. Beat for 2 to 3 minutes, until very smooth and light.

Add the powdered sugar 1 cup at a time. Once incorporated, add a splash of heavy cream at a time to help loosen up and fluff up the buttercream. Add the vanilla and salt. Beat for 3 to 4 minutes, until light and fluffy.

Add a thin layer of frosting around the top and sides of the sheet cake. You are creating a blank canvas for your design!

Add the blueberries in a square at the upper lefthand corner. Transfer a small amount of frosting to a piping bag with a small star tip. Pipe small star mounds in between the blueberries.

Alternate between layers of raspberries and buttercream (in a larger star tip piping bag) for the red and white stripes.

Keep away from direct heat and sunlight prior to serving. Best decorated day of serving.