This is such a treat at our house! You can make it with fresh or frozen blueberries, but of course fresh are best, which makes it perfect for the 4th of July since that's when blueberries are in season. This year my dreams came true because I was able to use blueberries from our very own bush!
Preheat oven to 350 degrees. Grease and flour a 10-inch bundt pan, as well as a smaller pan (like a bread loaf pan). This recipe makes way too much for just one cake pan, so have an extra pan ready.
2 cups (4 sticks) butter, softened
3 cups sugar
6 large eggs
In a large mixing bowl, beat butter with an electric mixer (or your Bosch or Kitchen Aid) until creamy. Gradually add sugar, beating well. Add eggs one at a time, mixing well after each one and scraping down the sides of the bowl if necessary.
In a separate large bowl combine:
4 cups flour
1 TBS baking powder
1/2 tsp salt
In a liquid measuring cup:
1 cup milk
Alternately add flour mixture and milk to butter mixture, beginning and ending with flour.
Stir in:
2 tsp vanilla
Fold in:
2 cups fresh or frozen blueberries
Pour batter into prepared pans. Place in preheated oven for 1 hour plus 30-40 minutes. The smaller pan will only need 45 minutes to an hour, but the bigger one will need over an hour. Since all ovens are different, and so are altitudes, check the oven after an hour (for the bigger cake). The cake should have a dark-ish golden color to it. It may look burned, but it's not. If you want, you could cover the cake with foil halfway through cooking to prevent over-browning, but I have never done that.
Place cooked cake on a wire rack to cool.