This American flag cake is moist and flavorful with a beautiful texture and a flag made out of berries. It's easy to make from scratch with simple ingredients and is a perfect patriotic dessert for any holiday!
Preheat oven to 350 degrees Fahrenheit (177 degrees Celsius).
Line a sheet cake pan with parchment paper and lightly grease, set aside.
In a medium bowl, combine flour, baking soda, baking powder, and sea salt. Set aside
Whisk the melted butter, sugar, eggs, sour cream, milk and vanilla in a large bowl until the mixture is smooth.
Add the dry ingredient mixture to the wet ingredients and whisk until combined and there are no lumps.
Evenly spread the batter into the prepared sheet cake pan.
Then, bake the vanilla sheet cake in the preheated oven for 28-33 minutes, or until a toothpick inserted in the center of the cake comes out clean or with a few crumbs.
Place cake pan on a wire cooling rack to cool to room temperature (takes about 30 minutes).
Once cool, you can either lift the cake out of the pan and transfer it to a rectangular serving platter, or leave it in the pan and frost.
Make the Vanilla Buttercream Frosting
In the bowl of a standing mixer fitted with the paddle attachment, or in a large bowl with a handheld mixer, beat the butter, vanilla and sea salt for 1 minute.
Add 2 cups of the powered sugar, and beat until combined.
Then, add the milk and 3 more cups powdered sugar (you should be up to 5 cups by this time), and beat until smooth.
Add the additional 2.5 cups powdered sugar and beat until smooth and fluffy.
Assemble the Flag Cake
Let the cake cool completely before spreading the vanilla frosting evenly over the cake.
Arrange the fruit on the cake as follows: make 7 rows of 7 blueberries (add an extra somewhere if desired) in the upper left hand corner of the cake (represent the stars)
Then, make 7 horizontal rows of strawberries evenly spaced down the cake for the stripes (see photos)
Chill for at least 1 hour before serving.
Cut into pieces and serve
Video
Notes
Ingredient Substitution Notes
All-purpose flour. Cake flour is a good substitute.
Salted butter. Unsalted butter works well!
Granulated sugar. white sugar or organic cane sugar yield the best results.
Whole milk. 2% milk or heavy cream are good substitutes.
Sour cream. Full-fat, plain Greek yogurt can be used in place of sour cream. I recommend using full-fat ingredients.
Vanilla extract. You can substitute up to ½ teaspoon of the vanilla extract with a flavored extract like almond, orange, etc.
Stars & StripesI like using fresh berries, you could also use blue and red frosting and pipe the stars and stripes onto the cake if you prefer.
Blueberries. I suggest keeping the cake red white and blue. Blackberries and concord grapes are a good substitute for blueberries, although they are larger so you will need less.
Strawberries. cherries (pitted and halved) and raspberries are great red fruits to use in place of or in addition to strawberries.
StoreStore leftover cake in an airtight container in the refrigerator for up to 5 days.FreezeOr, freeze individual slices by flash-freezing them on a baking sheet. I recommend removing the fruit - and serving with fresh fruit after thawing, since berries release a lot of water as they thaw.Then, wrap the frozen cake slices in plastic wrap and store in an airtight container for up to 1 month. Thaw slowly in the refrigerator overnight or at room temperature.