This is my favorite type of warm weather cake It's sweet and citrusy with a light crumb that is as sunny as the weather. Because the cake uses a large quantity of lemon zest, we like to serve it with homemade lemonade. Waste no, want not!
Before starting, bring the eggs, butter, cream cheese, lemons and blueberries to room temperature. This is a very important step! Depending on weather this can take 1-2 hours.
Preheat the oven to 350 and grease and flour two 9 inch by two inch cake pans and line the bottom of each with a piece of parchment cut to fit.
Place the blueberries in a bowl.
Sift and measure the flour, or weigh it and place it in a medium sized bowl.
Take a teaspoon of the flour and add it to the blueberries. Gently stir to cover the berries in flour.
Add the baking powder, baking soda and salt to the flour and whisk to combine.
In the bowl of an electric mixer with a whisk attachment, whip egg whites to soft peaks then transfer to a bowl.
Change the beater to a paddle attachment and beat the butter until soft and fluffy.
Stir in the sugar and mix on medium speed for another minute.
Add in the lemon zest and beat on high speed for about 30 seconds.
Drop in the egg yolks one at a time beating a little between each addition.
Add in the extracts and lemon juice and mix on low speed to combine.
Pop open the champagne and measure out one cup into a liquid measuring cup. Make sure the liquid is at the one cup mark after the foam has settled!
Starting and ending with the flour, alternatively mix in dry ingredients and the champagne in three additions. Make sure to mix on low speed and beat each addition until just incorporated.
Fold in the egg whites by hand with a spatula.
Finally, gently fold in the blueberries.
Evenly divide the batter between the two pans and transfer to the oven.
Bake 25-30 minutes, or until the cake springs back to the touch and the sides have pulled away from the pan. Alternatively, use a tooth to test doneness.
Remove from the oven and let cool in the pan for 5-10 minutes.
Run a knife along the edge, and gently turn out the cake onto a cooling rack. I prefer to flip the cake again so the parchment is resting on the rack. This way it won't stick.
Let cake cool completely before frosting.
Cream butter in the bowl of an electric mixer.
Add in powdered sugar one cup at a time. By the time you get to the end, the mixture will most likely resemble a course crumb. Go with it, you're on the right path!
Pour in the extracts and mix thoroughly.
Finally add in the cream cheese a little at a time, whipping on low speed at first and increasing the speed at the end.
Remove parchment from cakes and frost with an offset spatula.