Preheat your oven to 325°F.
Grease and flour your bundt pan.
Cream the butter, shortening, and sugar together in an electric mixer on low speed until it is light and fluffy. Then add eggs and extracts in and mix it well.
In a separate bowl, combine the flour and baking powder together.
Take your flour mixture and add a little of that to your sugar mixture, then a little of the milk, back and forth alternately to the sugar mixture. You can do this on medium with your mixer until it is all combined.
Put about 1 cup of your blueberries into the bottom of your bundt pan.
With a spoon, fold the rest of your blueberries into the cake batter.
Pour the batter into your bundt pan.
Bake the cake for 1 1/2 hours or until an inserted toothpick comes out clean.
When the cake is finished, allow the pan to sit on a wire rack until it is completely cooled. Carefully run a butter knife around the edges of the pan to help loosen the cake.
Put your cake plate on top of your pan and flip it over to place your cake on the plate.
Dust the outside of the cake with just a little bit of powdered sugar.