Preheat oven to 375° and spray a 9" baking pan or springform pan with non-stick spray.  Cut out a circle of parchment paper to fit in the bottom of the pan for easier transfer to a serving dish.

Crumb Topping

In a medium bowl, combine the crumb dry ingredients and stir.  Cut the butter into smaller pieces and mix with the dry ingredients until the butter is combined.   Refrigerate the mixture until ready to use.

Cake

In a large mixing bowl, combine the butter and sugar and cream together with a mixer until fluffy.  Add the egg, milk and vanilla extract and mix again.  Add the flour, baking powder and salt and mix to combine with the butter mixture.

The batter will be thick, but it works I promise.

Sprinkle the blueberries with 1 teaspoon of flour to coat so they don't fall to the bottom of the cake.

Fold the blueberries into the batter.

Pour the batter into the prepared pan and top with the crumb streusel topping in marble-sized chunks.

Bake for 55 - 60 minutes until the top is golden brown and the center is firm.  Toothpick should come out clean when testing for doneness.

Remove from the oven and cool for 10 minutes on a wire rack.

Glaze

The glaze is definitely optional but looks beautiful and adds a little something-something to the cake to make it extra special and indulgent.

Prepare glaze while the cake is cooling.  In a small bowl, combine powdered sugar, vanilla and milk until smooth and pourable.

Pour the glaze over the top of the warm cake for a glaze that hardens and melts into the cake.