Preheat oven to 350° F.

Line 9x13 pan with parchment paper, set aside.

In bowl of mixer add the butter and mix until pale yellow.

With mixer on medium speed, stream in the sugar and mix until combined.

Add in the eggs, one at a time, oil, and vanilla.

Mix until combined. Scrape bowl as needed.

With mixer on low speed add the baking powder and salt.

Alternate between the flour and milk, starting with flour and ending with flour.

Mix until combined.

Pour batter into prepared pan and smooth out evenly.

Bang pan on counter to remove any air bubbles.

Bake for 45-50 minutes or until center bounces back when gently pressed on.

Remove from oven and let cool completely.

In the bowl of a mixer fitted with the paddle attachment, add the butter and beat on medium/high speed. Mix until butter is pale yellow.

Alternating between the powdered sugar and the heavy cream, start adding both with mixer on low speed. Increase speed to incorporate completely.

Slowly add in the milk, mix on low until incorporated.

Bring mixer up to medium speed and add in the vanilla and almond extracts.

Mix on high speed until smooth and creamy.

Cut your raspberries in half and your strawberries into quarters. Blackberries will remain whole.

Place cake on a cake plate or cake board.

Using a rubber spatula, scoop buttercream onto the cake, as much as you need for the top and sides.

Using a large, metal, offset spatula, spread the buttercream evenly over the cake and the sides. It doesn’t need to be perfect, the goal is a nice flat surface.

Gather your berries and start with the stars section of the design by making a rectangle of blackberries where the stars would be.

Next make the red stripes, each band is an alternating line of either raspberries or strawberries. Arrange them closely.

Cut the cake and serve.

Extra buttercream can be stored in an airtight container and refrigerated.