Love coconut cake but don’t want to spend two days making a layer cake? This coconut sheet cake is incredible — and can be whipped up in 10 minutes flat, baked in 15 minutes flat, frosted in 10 minutes flat, and eaten in… well, you can imagine. There is a 3-hour chilling time in the middle, but what’s hard about throwing something in the fridge? I think you could probably half this recipe to bake in an 8-inch square pan, but I haven’t tried. Let me know if you do!
1 cup butter
1 cup water
2 1/4 cups cake flour
2 cups white sugar
2 eggs, lightly beaten
1/2 cup sour cream
1/4 teaspoon vanilla extract
3/4 teaspoon coconut extract
1 teaspoon baking soda
1 teaspoon salt
1/2 cup canned coconut milk, shaken
Whipped Coconut Icing Ingredients:
1 1/2 cup milk
7 tablespoons plus 1 1/2 teaspoons flour
1 3/4 cups plus 2 tablespoons granulated sugar (not powdered sugar)
1 1/2 teaspoons vanilla extract
1 1/2 teaspoons coconut extract
3/4 cup butter, at room temperature
3/4 cup coconut plus more for topping
Make the cake: Preheat the oven to 375 degrees and spray a 15 x 10 x 1″ baking sheet with PAM Cooking Spray. In a medium saucepan over medium heat, bring the butter and water to a boil. In the meantime, in a separate large bowl, whisk together the cake flour and sugar before adding the eggs, sour cream, vanilla extract, coconut extract, baking soda, and salt. Mix to combine. While mixing, slowly pour in the boiling butter and water mixture. Mix to combine completely. Your batter will be very runny. Pour the batter into the prepared baking sheet.
Bake at 375 degrees for 15-17 minutes or until a toothpick inserted in several places comes out with a few moist crumbs (don’t wait for the top to get golden brown, necessarily — mine stayed pale). After it’s cooled for 10 minutes, poke holes throughout the cake with a fork. Pour the coconut milk evenly over the cake. Cover the cake and chill it in the fridge for 3 hours or overnight.
Make the frosting: heat the milk, flour, and granulated sugar together over medium heat, whisking constantly. Once it starts to boil, continue whisking and heating it for around 7 minutes or until it’s very thick, like cake batter consistency. Remove the mixture from the heat and add the extracts. Remove the mixture to a shallow pan and let the mixture cool completely (after a bit, I stuck mine in the fridge to hurry it along). Once the mixture is cool, beat the butter in the bowl of a stand mixer until soft and fluffy. Add the completely cooled mixture and beat on high until you have fluffy frosting the consistency of stiff whipped cream. Mix in the coconut. Frost your completely cooled cake with a thick layer. Sprinkle more coconut on top. Store leftovers in an airtight container in the fridge, but be sure to let it sit out for 30 minutes before serving so the frosting can soften.