Preheat oven to 350 degrees. Grease a bundt pan very well and lightly dust with flour.
Cream together the sugar, cream cheese, butter and vanilla well. Add the eggs one at a time, beating well after each addition.
Sift together the flour and baking powder. Gently fold dry ingredients into the creamed mixture until the flour is almost fully incorporated. At that point fold in the blueberries.
Bake for about 1 hour or until toothpick inserted comes out clean. Baking times may vary considerable, especially if you are using frozen berries which can add 15 - 20 minutes. Watch cake closely and rely on the toothpick test to make sure that it is completely baked.
Cool on a wire rack for 15 minutes before turning out of pan onto the rack to cool completely.
Whisk together the powdered sugar and lemon juice until smooth. Use only enough lemon juice to bring the glaze to a thick, but still pourable consistency.