New Hampshire Blueberry Cake

1/3 cup butter
1 cup sugar
1 large egg
2 cups sifted all-purpose flour
1 tsp. baking soda
1/2 cup sour milk or buttermilk
3 cups fresh blueberries (or fresh frozen)

Cream butter until light; add sugar and continue beating until fluffy. Beat in egg.

Mix flour and soda and add alternately with the sour milk, beginning and ending with the dry ingredients. The batter will be very stiff to hold the load of blueberries now added after patting dry. Stir into batter and spread batter in a well-greased 9 x 9 x 2-inch baking pan.

Bake in 325 degrees oven for 45 to 50 minutes until cake is nicely browned on top and has pulled from sides of pan. Cool cake upright in its pan on a wire rack to room temperature before cutting.