Preheat oven to 375 degrees. Lightly grease an 8 X 11 or 8 X 8 inch baking pan.
Cream butter; add sugar and beat well.
Beat in eggs one at a time.
Sift flour, baking powder and cinnamon together. Gradually stir into creamed butter and sugar.
Spread 3/4 of dough in greased pan.
Spread blueberry pie filling over dough.
Spoon remaining dough over pie filling, spreading lightly. *Note: Not all pie filling will be covered.
In separate small bowl, combine streusel ingredients and then sprinkle over top of bars.
Bake at 375 degrees for 35-40 minutes.
Cool for 15 minutes.
In a small bowl, mix powdered sugar, milk, and vanilla until smooth; drizzle over bars.