1Preheat oven to 350 degrees. Adjust oven rack to center position. Grease and flour a 12 cup bundt pan.
2In a medium mixing bowl, whisk together flour, baking soda, baking powder, and salt. Set aside.
3In a small bowl, toss 1 1/2 cups fresh blueberries in 1 tbsp of flour; set aside.
4Grate the lemon zest in a cup. For the cake, grate 2 tbsp of zest. If also using on top of the glaze, grate an additional 1 tbsp.
5In a large mixing bowl with electric mixer on medium, cream together the butter and sugars. Add the eggs, one at a time and mix well.
6Beat in the vanilla and 2 tbsp lemon zest and 1 tsp lemon extract (or 2 tsp of fresh lemon juice).
7Add the flour mixture to the liquid ingredients with mixer on low. Add the flour in alternately with sour cream (ending with flour).
8Fold the floured blueberries into the cake batter with a spoon.
9Spoon the batter into the prepared bundt pan and spread around evenly.
10Bake for 45-50 minutes or until a toothpick tests done.
11When finished, let cake rest for 15 minutes upright on cookie rack.
12Loosen cake from pan and flip over to release on a cake dish or plate. Let cool completely.
13Make the glaze to drizzle over cooled cake if desired. In a small bowl, whisk together 1-1/2 cups of powdered sugar, milk and lemon juice or extract.
14When glaze is smooth in consistency, drizzle with a spoon over top and down sides of cake. Top the glaze with 1 tbsp grated lemon zest and blueberries around the top in a ring. If not using a glaze, sprinkle top of cooled cake with powdered sugar.
15Store tightly covered in a cool place or refrigerator.