Spray an 8x8 baking pan with nonstick spray and set aside.
In a small bowl add the 1 Tablespoon of flour to the blueberries and gently stir to coat blueberries with flour. Set aside.
In a medium bowl whisk together the 2 cups of flour, baking powder, and salt. (whisking will remove any lumps in the flour). Set aside.
In a large bowl cream together the sugar, ¼ cup butter and egg on medium-high speed with a hand held mixer for 1-2 minutes. Add the milk and mix on low speed until smooth, 1-2 minutes.
Next add the dry ingredients and stir just until mixed.
Gently stir in the flour-coated blueberries.
Spread mixture evenly into the prepared pan.
In a small bowl mix together with a fork the topping ingredients of brown sugar, 3 Tablespoons flour, 3 Tablespoons of butter and cinnamon until it is crumbly. Sprinkle on top of the coffee cake batter.
Bake for 35-40 minutes or until the cake tester comes out with just a few crumbs on it. Let it sit in the pan for 10 minutes before serving.
Be sure to actually cream together the sugar and butter. How do you cream together ingredients? What does it mean to cream? It is more than just mixing them together, you are blending them to create a fluffy yellow mixture. Make sure your butter is at room temperature. The butter should be soft, but not melted. Slice the butter into small cubes and place it in the bowl with your sugar. Gently mash the butter using the tines of a fork. Then use a wooden spoon to mix together the sugar and butter until you it has almost doubled in size and has a light yellowish color.
All ovens are going to bake a little differently. You need to watch your cake so you get that perfect moist finish. You can tell when the cake is done when a toothpick inserted in the center comes out clean (but not totally dry). If you have a few crumbs on the toothpick, that is fine! Just not sticky and wet!
Consider testing your coffee cake about 5 minutes before the end of the baking time, just to be sure to not over cook it. Nothing is worse than a dry coffee cake.
Experiment with other mix-ins! Any type of fresh fruit can be substituted in. We have been known to throw in some chocolate chips or cinnamon chips for fun.
Try adding a streusel topping. Streusel makes everything yummier!