preheat the oven to 350°F (176°C)
grease and flour a 12 cup bundt pan.
Beat the butter in the bowl of the stand mixer on medium until creamy about 1 minute.
Add the sugar to the butter and beat on medium for 2 minutes, scrape the edges of the bowl after one minute and after 2 minutes
Add the vanilla to the eggs (6 whole eggs and 6 egg yolks) and whisk to mix. Discard the whites from 6 of the eggs or save the whites to use in a different recipe.
Add the eggs to the sugar-butter mixture 1/6th of the total at a time. Beat on low between each addition of the eggs until the eggs are well mixed in. Once all the eggs are mixed in, scrape edges of the bowl. Then on medium beat the batter for another 2 minutes and scrape the edges down again.
Add the salt to the flour and mix together. Add the flour to the batter with the mixer on low. Add 1/4 of a cup at a time, beating between each addition until all the flour is mixed in. Scrape the sides of the bowl again and then beat a final 2 minutes on medium.
Split the blueberries in half and add 1 tablespoon of flour to 1/2 of the berries. This keeps the berries from sinking to the bottom of the pan. Do not flour the other half and it will sink to the bottom of the pan during baking giving the cake lots of beautiful berries that will be visible when you unmold the baked cake.
Add the batter to a greased and floured bundt pan
Sprinkle the lemon streusel on top of the cake.
Bake at 350°F for 60-70 minutes or until a toothpick inserted in the center of the deepest part comes out clean.
Cool for 30 minutes on a wire rack and then invert onto a serving plate. Cool another 30 minutes before glazing.