Such a fun way to start the day! Blueberry Coffee Cake is as easy as it is delicious.
In a stand mixer (or using a hand-held mixer) cream butter and sugar until fluffy, about 2-3 minutes.
Add dry ingredients to butter mixture and blend on medium for 30 seconds, mixing until ingredients are JUST incorporated.
Place batter in a prepared 9x13 casserole pan. Prepare crumble and add it on top of the batter. (directions below)
Using a food processor, fork, or your hands, combine brown sugar, flour, cinnamon, and cold butter pieces in a bowl. (I prefer clean hands) Make sure the butter is broken down and no larger than a pea when you are done.
Bake coffee cake at 350°F for 35-40 minutes or until an inserted toothpick comes out mostly clean. If your top is starting to brown, cover the coffee cake with foil.
Combine the powdered sugar and milk. Feel free to add a few drops of additional milk at a time until it reaches drizzling consistency.
Drizzle glaze over a warm cake and serve.