Preheat the oven to 350 degrees F and lightly grease and line a 9' x 13' pan with parchment paper, leaving extra hanging over the sides for easy removal. Set aside.

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

In a larger bowl, use an electric mixer to beat the butter and sugar until light and fluffy, about 3-5 minutes.

Add in the eggs one at a time, mixing well after each addition. Stir in the vanilla.

Alternate adding the dry ingredients and buttermilk, starting and ending with the dry ingredients. Mix lightly with a silicone spatula until combined.

Pour half of the batter into the prepared pan and bake for 12-15 minutes or until golden brown. Use a spatula to spread the batter evenly in the pan.

Let the first cake cool in the pan for about 5 minutes before transferring to a wire rack to cool completely. Repeat the process for the second batch of batter.

Allow both cakes to cool completely before decorating. Wrap them in plastic wrap and chill in the fridge for an hour.

For the buttercream, mix the butter and confectioners sugar on low speed while slowly adding heavy cream, one tablespoon at a time, until smooth. Scrape down the bowl as needed.

Add the vanilla and salt to the buttercream.

Once cooled, cut the cakes into Christmas tree shapes. A stencil can help if you want to ensure they are identical.

Place one cake face down on a serving dish and add a layer of buttercream on top. Line the second cake beside it and flip it on top.

Apply a thin layer of buttercream all around the cake (crumb coat) to trap any crumbs. Chill in the fridge for one hour.

Frost the cake again with a thicker layer of icing. Use a spatula for a smooth finish.

Dye about 1/4 of the buttercream red for decorations. Once frosted, add green sprinkles and pipe on red lines.

Enjoy!