Gluten Free Lemon Blueberry Cake

There are a few desserts that just say summer to me. Lemon cake is one of them, and this gluten free lemon blueberry cake is the layer cake of my summer dreams.

The lemon buttercream filling in the center with a rich lemon glaze on top pair perfectly with the lightly sweet, tender lemon cake. The sweet late-spring fresh blueberries don’t hurt, either.

Resist the temptation to pack the cake with ever more blueberries. They’ll make for a too-wet cake that rises and then sinks, leaving you with an overly wet, dense cake. Not exactly what we’re going for!

If you’d rather not make a lemon buttercream filling and a separate rich lemon glaze for the top, feel free to double up on the buttercream.

But if you ask me the rich lemon glaze on top is what pushes this summer cake from really good … to spectacular!

Prep time: 20 minutes       Cook time: 20 to 25 minutes       Yield: 1 9-inch layer cake

Ingredients

For the cake
2 cups (280 g) all purpose gluten free flour (I used my Better Than Cup4Cup blend)

1 teaspoon xanthan gum (omit if your blend already contains it)

1/4 cup (36 g) cornstarch

1 1/2 teaspoons baking powder

1/2 teaspoon baking soda

3/4 teaspoon kosher salt

3/4 cup (150 g) granulated sugar

Zest of 2 lemons, finely grated

1/2 cup (109 g) packed light brown sugar

12 tablespoons (168 g) unsalted butter, at room temperature

3 eggs (180 g, out of shell) at room temperature, beaten

1 teaspoon pure vanilla extract

1/4 cup (2 fluid ounces) freshly-squeezed lemon juice (from about 2 medium-size lemons)

3/4 cup (180 g) sour cream, at room temperature

1 1/4 cups (150 g) fresh blueberries, tossed with 1 teaspoon cornstarch

Lemon Buttercream Frosting
16 tablespoons (224 g) unsalted butter, at room temperature

3 1/2 to 4 cups (400 to 460 g) confectioners’ sugar

1/2 teaspoon kosher salt

3 to 4 tablespoons freshly squeezed lemon juice (from about 2 medium-size lemons)

Rich Lemon Glaze
2 to 2 1/2 cups (230 to 290 g) confectioners’ sugar

1/8 teaspoon kosher salt

3 tablespoons freshly squeezed lemon juice (from about 1 large lemon)

2 tablespoons (28 g) unsalted butter, at room temperature

More fresh blueberries for decorating

Directions

• First, make the cake. Preheat your oven to 350°F. Grease and line two 9-inch square (or round) cake pans and set them aside. In a large bowl, place the flour, xanthan gum, cornstarch, baking powder, baking soda, salt and granulated sugar, and whisk to combine well. Add the lemon zest, and whisk into the dry ingredients to ensure that the lemon zest isn’t clumped. Add the brown sugar and whisk again, working out any lumps. Create a well in the center of the dry ingredients and add the butter, eggs, vanilla, lemon juice and sour cream, mixing to combine after each addition. The batter will be thick. Add the blueberries tossed in cornstarch, and fold carefully into the batter until the blueberries are evenly distributed throughout. Divide the cake batter evenly among the two prepared pans and spread into an even layer. Place in the center of the preheated oven and bake until a toothpick inserted in the center of each cake comes out clean (20 to 25 minutes), rotating once during baking. Remove from the oven and allow to cool in the pans for 10 minutes before transferring to a wire rack to cool completely.

• While the cakes are cooling, make the buttercream frosting. Place the butter in the bowl of your stand mixer fitted with the paddle attachment (or a large bowl with a handheld mixer) and beat on medium speed until the butter is light and fluffy. Add 3 1/2 cups of the confectioners’ sugar and the salt, and mix on low speed until the sugar is absorbed into the butter. Increase the speed to medium-high, add the salt and lemon juice, and continue to beat until the frosting is light and fluffy (about 3 minutes). Add more confectioners’ sugar by the tablespoon as necessary to bring the frosting to a thickly spreadable consistency.

• Assemble the cake. Invert one of the cooled cakes onto a cake stand or other serving platter, and spread all of the buttercream frosting into one thick, even layer on top. Invert the second cake on top of the frosting and press down evenly on top.

• Make the lemon glaze. In a medium-size bowl, place 2 cups of the confectioners’ sugar and the salt, and whisk to combine well. Add the lemon juice and the butter, and mix to combine. Add more confectioners’ sugar as necessary to create a very thickly pourable glaze. Pour the glaze on top of the layer cake and spread into an even layer on top, allow it to drip down the sides. Scatter a few more fresh blueberries on top of the glaze. Allow to set either at room temperature or in the refrigerator before slicing and serving. For clean slices, chill the cake before slicing.