INGREDIENTS
1 cup
Blueberries, fresh
1/2
Lemon, Zest of
1
Egg white, large
1/4 tsp
Baking soda
1 cup
Cake flour
1
Powdered sugar
1/4 tsp
Salt
2/3 cup
Sugar
1/2 tsp
Vanilla extract
1/2 cup
Butter, unsalted
1/2 cup
Buttermilk
A heavy/slightly rounded 1/8 tsp baking powder