Preheat oven to 350 degrees. Coat a 10-inch Bundt pan with baking spray.
Make the filling by mixing together brown sugar, flour, cinnamon, and melted butter. Set aside.
In a large bowl, cream together butter and sugar. Add eggs, one at a time. Add milk and vanilla. Add flour, baking powder, and salt. Stir in blueberries.
Fill the Bundt pan with about 1/3 of batter. Spoon 1/3 of filling evenly over batter. Add another 1/3 of batter, then top with 1/3 of filling. Repeat with remaining batter and filling.
Bake at 350 degrees for 45 minutes to an hour, or until a cake tester inserted in center comes out clean. Cool in pan 10 minutes before removing. Let cake cool until slightly warm to the touch before drizzling with glaze.
To make the glaze, mix together confectioner's sugar, milk, and vanilla. Stir until smooth. Pour over cake before slicing.