Prepare and bake Dessert Crust. Reduce oven temperature to 350 degrees F. In a medium saucepan, combine 3 cups blueberries, the 1/3 cup sugar, the tapioca, water, cinnamon, lemon peel, and nutmeg. Let stand for 15 minutes. Cook and stir mixture over medium heat until blueberries become juicy and mixture is bubbly. Turn into partially baked Dessert Crust.
In a medium mixing bowl, combine sour cream, egg yolks, the 1/2 cup sugar, and the vanilla. Pour evenly over blueberry mixture.
Bake about 50 minutes or until sour cream layer is set when gently shaken. Cool in pan on a wire rack for 1 hour. With a sharp knife, loosen crust from side of pan; remove side. Cover and chill overnight before serving.
To serve, if desired, garnish with additional blueberries. Makes 12 to 16 slices.
Preheat oven to 400 degrees F. In a large mixing bowl, beat butter with an electric mixer on medium to high speed for 30 seconds. Beat in sugar, baking powder, and salt until combined. Beat in egg yolk. Add flour; beat until combined. (Mixture will be crumbly). Work dough mixture with your hands just until mixture holds together. Press the mixture on the bottom and 1-1/2 inches up the side of an 9-inch springform pan. Bake for 12 minutes or until edges of crust are lightly browned. Cool on wire a rack while preparing filling.