Preheat the oven to 350 ºF. Spray a 9-inch spring-form pan with baking spray and set aside.
In a large stand mixer, cream together the butter and sugar.
Add the eggs and vanilla to the butter mixture, and scrape down the sides of the bowl as needed, until fully incorporated.
Add the flour, baking powder, baking soda and salt, and mix on low speed until just combined.
Add the sour cream and mix for 60 seconds more, until fully incorporated.
In a medium bowl, combine the ingredients for the topping and, using a fork or a pastry cutter, cut in the butter until you have a crumbly mixture.
Transfer half of the batter to the prepared spring-form pan and smooth out so it covers the bottom. Sprinkle ½ cup of the streusel topping on top of the batter, and then cover with the remaining batter.
Sprinkle the remaining streusel on top of the batter. Transfer the spring-form pan onto a baking sheet and then into the prepared oven.
Bake for 55-60 minutes, until a knife can be inserted into the center and comes out clean. Remove from the oven. Let the cake cool completely.
In a small bowl, whisk together the powdered sugar and milk until smooth.
Drizzle the glaze over the cooled cake and serve with coffee.