Adapted from Salt Water Seasonings: Good Food from Coastal Maine
Makes one 8-inch square cake
This cake is all the rage at my camp up in Maine. Everyone up there makes a version of it but this one seems to be the most popular!
1-1/2 cups flour
1 teaspoon baking powder
1/2 teaspoon salt
1/2 cup (1 stick) unsalted butter, at room temperature
1 cup plus 2 tablespoons sugar
1 teaspoon vanilla extract
2 eggs, separated
⅓ cup whole milk
1-1/2 cups fresh blueberries, tossed with 1 tablespoon flour, or 1 1/2 cups frozen wild blueberries (if frozen, do not defrost or toss with flour)
Set the oven at 350 degrees. Butter an 8-inch square cake pan.
In a bowl, whisk the flour, baking powder, and salt to blend them.
In an electric mixer, cream the butter and 3/4 cup of the sugar until light and fluffy. Beat in the vanilla, followed by the egg yolks and beat until smooth. Add the flour mixture to the batter alternately with the milk, beginning and ending with flour. Remove the bowl from the mixer stand.
In another bowl, beat the egg whites with 1/4 cup sugar until stiff but not dry. Gently but thoroughly fold the whites into the batter. Fold in the blueberries.
Spread the cake evenly in the pan. Sprinkle the remaining 2 tablespoons of sugar. Bake the cake for 50 to 60 minutes or until the cake springs back when lightly pressed.