FOR CAKE –
Preheat oven to 350 degrees. Grease and line a 6″ cake pan with parchment paper on the bottom. In a large bowl, sift together the flour, cake flour, baking powder, and salt. Set aside.
In a 2 cup measuring cup, stir together the milk, half and half, lemon juice, lemon zest, sour cream, and vanilla bean paste (or extract). Set aside.
In a stand mixer, with a paddle attachment, beat together the softened butter and sugar until light and fluffy – about three minutes. Scrap the sides if needed. Add in eggs, one at a time, being sure to mix in completely before adding in another. At least 30 seconds should be good between eggs.
Add in the dry ingredients in three parts, adding in some of the milk mixture in between additions of flour. Scrape the bowl to ensure everything is mixed together and the batter is smooth. Let the batter rest for 15 minutes.
Fill the cake pan 1/2 to 2/3 full. Bake on the center rack, starting for 30 minutes. Check with a toothpick to test doneness. If it requires additional time, bake in 5 minute intervals until a toothpick comes out clean. For my 6-inch cake pans, it can take up around 40 minutes.
Let the cake rest on a wire rack in the pan for 5-10 minutes, before removing from the pan. Run a knife along the edges to ensure that it hasn’t stuck, and turn out onto wire rack to cool completely.
*If you are using a 9″ cake pan – bake for 30-35 minutes. For cupcakes – bake for 20 minutes.
For Elderflower Buttercream –
In a clean stand mixer fitted with a paddle attachment, cream the butter until smooth. Scrape down sides of bowl to ensure all the butter is creamed and smooth. With the mixer on low, add in the sifted powdered sugar one cup at a time until it is fully incorporated. When all the sugar has been added, scrape the sides of the bowl, to ensure it is all mixed in correctly.
Add in the St. Germain, and vanilla and salt. Turn the mixer on, working your way up to medium and allow the frosting to whip for about five minutes. Scrape the bowl every couple of minutes to make sure there is no dry frosting on the bottom. The buttercream will look soft, and then will continue to stiffen as it is beaten and increase in volume. Use right away or store in an airtight container in the fridge for up to one week.
To Assemble –
In two or three small bowls, add in 1/2 cup of frosting, and dye to the desired colors. Frosting darkens over time, so be sure to tone your frosting slightly LIGHTER than you want the final color to be. Set aside, or into piping bags.
Level the cakes, and placing the cut side down on a cake serving dish, Spread an even layer of frosting on top of the cake. Place the second layer on top of the cake. Repeat frosting the cake, all around, and smoothing out. This doesn’t need to be perfect, but evening out the frosting here is best to ensure it’s distributed evenly.
With the colored frosting, make dime sized dots of colored frosting sporadically around the cake. Spread the dots out about 3 inches apart, but if they aren’t perfect, it will create a blended effect which is FUN! Using the spatula, spread the dots out to doing a final smoothing on the cake, which will naturally blend the colors dots into the white frosting. Don’t over smooth – this cake is meant to look rustic!
Decorate additionally with a spray of fresh flowers that match your frosting colors! Serve immediately or chill.