Preheat the oven to 375 degrees F (190 degrees C). Grease a 9 inch springform pan.

Stir flour, ½ cup sugar, and baking powder together in a medium bowl. Add butter by pinching between fingers or use a pastry blender until mixture resembles coarse crumbs. Stir in egg and 1 teaspoon of vanilla extract. Pat lightly into bottom of the prepared pan. Add blueberries.

Whisk sour cream, remaining ½ cup sugar, egg yolks, and remaining 1 teaspoon vanilla extract together in another medium bowl until smooth. Pour over blueberries.

Bake in the preheated oven until light brown, 60 to 70 minutes. Run a knife around edge of the pan once cake is cool. Remove the outer ring of the pan before serving.