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This oat flour Flag Cake is a fun, patriotic treat for a holiday weekend. It’s naturally dairy-free and gluten-free, and there are tons of options below to help you customize it to your needs.
This cake is the result of some experimenting I’ve done this week. I was testing different brands of coconut milk to make dairy-free whipped cream, and I’ve also been testing a new oat flour cake recipe.
Why not combine them and turn them into a dessert for the Fourth of July? This also works for Memorial Day and Labor Day. You can even make it into a Canadian Flag, using only strawberries, for Canada Day.
Why You’ll Love It
- It’s gluten-free. Made with oat flour, this cake is naturally gluten-free, but be sure to make sure the flour you’re using is “certified gluten-free” to prevent contamination during processing.
- It’s dairy-free. The batter uses coconut oil instead of butter, and the cake is frosted with coconut whipped cream. (Or, use my vegan cream cheese frosting.)
- It’s naturally sweetened. The cake is naturally sweetened with coconut sugar. Feel free to use any other granulated sugar you have on hand, though!
- It feeds a crowd. This cake yields 15 large slices, or more if you prefer to slice it smaller.
- It’s easy to decorate. No artificial food dyes are required to make this red, white, and blue cake. Slice some strawberries and have a cup of blueberries ready to go.
- You can make it ahead. Bake the cake the night before, and keep it in the fridge tightly covered overnight. You can frost and add the berries shortly before serving. (The berries can start to sweat into the white frosting if you prepare this too far in advance, FYI.)
Keep in mind that this flag cake is more of a general idea than a recipe that you have to follow 100% accurately.
If you want to use a different cake base, try:
Need a vegan recipe? Try these toppings on my Vegan Chocolate Cake, which is naturally grain-free and gluten-free.
Detoxinista Tip
If you’re using a different cake recipe that only makes one 8-inch cake, you must double the ingredients to fill a 9-by-13-inch pan. I’ve found that the baking time also needs to increase from 30 minutes to closer to 45 minutes when baking a cake this size, but be sure to keep an eye on the cake after the 35-minute mark, just to be sure.
How to Make a Flag Cake
- Stir. Start by whisking together the dry ingredients to break up any clumps. Then, add the wet ingredients and mix until smooth.
- Bake. Pour the batter into a greased 9-by-13-inch pan (or a similar rectangle pan for a flag shape) and bake until a toothpick inserted in the center comes out clean, about 45 minutes.
- Cool. Let the cake cool completely so the toppings won’t melt! I like to place mine in the fridge so it is cold when I frost it.
- Decorate! Top with coconut whipped cream or your favorite frosting, then add the blueberries and sliced strawberries. I usually can squeeze in about four rows of strawberry “stripes,” so it won’t be a perfect American flag, but I think you get the idea.
Flag Cake Frosting Ideas
Coconut Whipped Cream or your favorite store-bought whipped cream is the easiest topping for a flag cake. You can also make cream cheese frosting, if you prefer!
Use my dairy-free cream cheese for this idea:
- 1/2 cup vegan cream cheese, at room temperature
- 3 to 4 cups organic powdered sugar
- 1/2 teaspoon vanilla extract
Stir the ingredients in a large bowl, starting with just 1 cup of powdered sugar at a time, until it’s as thick as you’d like. This is not the type of frosting that can be “piped” or that will set. It remains relatively runny, so keep that in mind. My family didn’t care, since it tasted good!
Or, try my Vegan Cream Cheese Frosting made with white sweet potatoes.
Ingredients
- 3 cups oat flour (400 grams)
- 2 1/4 cups coconut sugar (367 grams)
- 4 large eggs (200 grams)
- 3/4 cup melted coconut oil (158 grams)
- 1 1/2 teaspoons baking soda (9 grams)
- 3/4 teaspoons salt (6 grams)
- 2 tablespoons vanilla extract (17 grams)
- 1 1/2 cups water
Toppings
- 2 heaping cups Coconut Whipped Cream (or 2 cups of your favorite frosting)
- 1 pound sliced strawberries
- 1 cup fresh blueberries
Instructions
- Preheat the oven to 350ºF and grease a 9-by-13-inch pan well. In a large bowl, combine the flour, sugar, baking soda, and salt, and whisk well, until there are no visible clumps.
- Add in the eggs, oil, water, and vanilla, and stir again, until the batter looks smooth. Pour it into the prepared pan and bake for 40 to 45 minutes, or until a toothpick comes out clean when inserted in the center.
- Let the cake cool completely before frosting. I like to place it in the fridge to cool, so the cake will be chilled when I frost it. Top the cake with coconut whipped cream or your favorite frosting (see recipe ideas in the post above), then top with sliced strawberries and blueberries to make an American Flag look, with the blueberries in the top left corner, and the strawberries making red "stripes."
- Serve this cake chilled, soon after adding the fruit. The sliced strawberries may start to sweat into the frosting if they sit for too long at room temperature. Store any leftovers in an airtight container in the fridge for up to 3 days. If you're planning to make this cake ahead of time, don't add the fruit until just before serving.
Notes
Nutrition
If you try this Flag Cake, please leave a comment below letting me know how you like it. And if you make any modifications, I’d love to hear about those, too.
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Reader Feedback: What’s your favorite treat to make for Fourth of July?
This cake is Amazing! All our friends and family are making it now. Thanks!