Preheat oven to 375˚F. Combine flour, sugar, and baking powder for cake in large bowl. Cut in butter, then stir in vanilla and egg. Mix until uniform in color. Turn out into 9” lined and greased springform pan. Press into bottom of pan.
Whisk together egg yolk, sour cream, sugar, vanilla extract, and almond extract for topping. Fold in blueberries. Pour over crust.
Bake for 60-70 minutes or until center is set and no longer jiggles when shaken. Allow to cool completely before removing from pan to serving dish.
Cut into slices to serve. Garnish with whipped cream if desired.