Preheat the oven to 350F degrees. Grease and flour a 9-inch springform pan.
In a medium bowl whisk together the flour, baking powder and salt.
In a large bowl beat together the butter, sugar, and lemon zest until fluffy.
Add in the vanilla extract and beat in the eggs 1 at a time.
In a liquid measuring cup, whisk together the milk and sour cream.
With the mixer on low speed, beat about ⅓ of the flour mixture into the butter mixture. Then beat in about ⅓ of the milk and sour cream mixture.
Repeat the process with the rest of the flour and milk and sour cream, until all the ingredients are combined. The batter will be thick. Be very careful to only mix until the batter is combined.
Spoon about ½ of the batter into the bottom of the prepared pan and spread smooth. Then sprinkle about ½ of the blueberries over top.
Spoon the rest of the cake batter over top of the blueberries & spread smooth. Cover the top of the cake with the rest of the blueberries, pressing them down slightly.
Bake in the preheated oven or 45-55 minutes, or until an inserted toothpick comes out clean (except for the blueberry juice.