• Preheat the oven to 375 degrees F (190 C).
• Prepare a 6 inch cake pan by spraying it with cooking spray.
• Cut a piece of parchment paper into a 6 inch circle. Place it in the bottom of the cake pan and spray again with cooking spray. Set aside.

For the Streusel Crumble:

• Combine the sugar, brown sugar, flour, cinnamon, and butter in a small mixing bowl with a fork until everything is combined and it forms a crumbly mixture.

For the Coffee Cake:

• In a large mixing bowl, combine the flour, sugar, butter, milk, egg, baking powder, and salt and stir together until smooth and combined.
• Gently fold in the blueberries until just barely incorporated.
• Spread the coffee cake batter into the prepared cake pan.
• Sprinkle the streusel topping evenly over the batter.
• Place the cake pan on a baking sheet and bake about 50 minutes. A toothpick inserted in the center should come out clean.
• Allow the cake to cool for 20 minutes.
• Loosen the edges of the cake from the pan with a knife.

For the Glaze:

• Combine the powdered sugar, milk, and vanilla in a small bowl until mixed well. Add more milk if it is too thick to drizzle.
• Drizzle the glaze over the coffee cake.
• Cut the cake into four equal slices and serve.