Grease and flour 9×13 baking dish
Preheat oven to 350°
Whish 2 cups of flour, baking powder, and salt together in medium bowl
In mixer, cream butter and sugars (white and brown) on a medium-sigh speed until fluffy
Add egss one at a time, beating until incorporated and scraping down bowl
Redice mixer speed to medium and add in ½ of flour mixture and mix until incorporated
Mix in ½ of milk
Add in ½ of the remaining flour mixture and continue to beat. Add in milk and then remaining flour
Toss blueberries with 1 tsp of flour
Using a spatcula, gently fold in the blueberries
Spread batter into prepaired pan
Scatter remaining blueberries over top of batter
Stir sugar and cinnamon together in a small bowl and sprinkle over batter
Bake until toothpick inserted in center of cake comes out clean; 45-50 minutes
