Instructions
1-Preheat oven to 350 F: Preheat oven to 350 F. Grease a 9-inch springform pan and line the bottom with parchment paper. Set aside.
2-To make the filling: To make the filling: Mix the cream cheese, sugar, and vanilla on medium-low speed until creamy. Add egg white and mix on low just to combine. Set aside.
3-To make the cake batter: To make the cake batter: In a bowl stir together flour, baking powder, baking soda, and salt, and set aside.
4-With an electric mixer cream together the: With an electric mixer cream together the butter and sugar on medium-low speed. Add egg, and egg yolk, and vanilla. Slowly mix in the flour mixture alternating with the sour cream. Transfer the batter to the prepared pan and smooth with a spatula. Sprinkle with 1/3 cup blueberries. Spread the cream cheese filling on top. Place remaining blueberries over cream cheese filling.
5-To make the topping: To make the topping: Combine sugar, flour, and chilled cubed butter in a bowl. Stir with a fork or pastry blender until the mixture is crumbly (Make sure the streusel is in pea-sized crumbs)
6-Sprinkle the streusel on top of the: Sprinkle the streusel on top of the blueberries and bake for 40-45 minutes until a cake tester inserted in the center comes out clean. If it starts browning too much, tent the top with aluminum foil.
7-Cool on a rack, run a thin: Cool on a rack, run a thin knife around the cake and loose ring of springform pan.
8-Store in the fridge: Store in the fridge.