Mix all ingredients together until crumbly; set aside.
Preheat oven to 350°. Grease a 13-by-9-inch pan.
Beat all cake ingredients, except blueberries, in a large bowl on a low speed for 30 seconds. Then beat on a medium speed for two minutes, scrapping bowl occasionally.
Spread half the batter in the pan. Sprinkle blueberries over the batter and then top with the rest of the batter. Add streusel topping and bake in oven for 30 to 40 minutes. Top with glaze after removing cake from oven.
Glazing for Coffee Cake:
Mix all ingredients together and drizzle on cake.
Judy Shortsleeve, our Business Manager, received this recipe in an L.L. Bean order many years ago—it was a favorite recipe of an L.L. Bean employee. I make this often and substitute other berries for the blueberries. Raspberries are very good and you can replace the vanilla with almond extract. This recipe also appeared in the 2013 Cape Cod LIFE Annual Guide.