This is from the PA Grange book with the red spine… page 290. Grandma had it marked as ‘the one i make’.
1/4 cup butter
3/4 cup sugar
2 cups sifted flour
2 teaspoon baking powder
1/2 teaspoon salt
1/2 cup milk
2 cups washed fresh blueberries
Cream butter and suger until light. Add egg and beat well. Add sifted dry ingredients alternately with milk, beating until smooth. Fold in berries, pour into greased 9x9x2 pan and sprinkle with crumb topping. Bake 35 minutes at 375.
Crumb topping: Blend together 1/4 cup soft butter,, 1/2 cup sugar, 1/3 cup flour, 12 teaspoon cinnamon.