Preheat oven to 350℉. Grease a 9-inch tube pan and set aside.
In a mixing bowl, mix 2 cups of flour, sugar, baking powder, baking soda, and salt.
In separate bowl, whisk eggs until frothy. Stir in yogurt and lemon zest. Slowly whisk in oil, blending well.
Pour wet ingredients into flour mixture. Partially mix together, then stir in blueberries until just combined and no more flour remains (batter will be thick). Scrape into tube pan, spreading out the top evenly.
In a bowl, mix together remaining flour, brown sugar, softened butter, and cinnamon until it resembles wet sand. Sprinkle evenly over coffee cake in pan.
Bake for 50-60 minutes or until the cake begins to shrink away slightly from the pan, and a toothpick inserted comes out clean. Let cool for approx. 30 minutes before removing from pan onto a cooling rack to cool completely.
In a small bowl mix together icing sugar, lemon juice, and milk or cream until smooth.
Using a spoon, slowly drizzle lemon glaze over the top of cooled coffee cake, allowing it to spill over the sides. Slice and serve.