Blueberry Cheesecake:

1. Preheat the oven to 350°F and prepare an 8-inch springform pan.
2. In a food processor, pulse the blueberries and cream cheese, then transfer the mixture to a mixing bowl.
3. Add sugar, flour, and vanilla, and beat until smooth.
4. Mix in the eggs, sour cream, and heavy cream.
5. Pour the batter into the prepared pan and bake in a water bath for 40-45 minutes.

Lemon Blueberry Cake:

1. Preheat the oven to 350°F and prepare two 8-inch round cake pans.
2. Sift together the flour, cornstarch, baking powder, and salt.
3. Beat butter and sugar until fluffy, then add eggs, vanilla extract, and lemon zest.
4. Alternate adding the flour mixture and milk mixture to the batter, then gently fold in the blueberries.
5. Divide the batter between the pans and bake for 30-35 minutes.

Lemon Cream Cheese Frosting:

1. Mix the butter and cream cheese until smooth, then add vanilla, salt, lemon zest, and powdered sugar.
2. Beat until smooth.

Assembling the Cake:

1. Once the cake and cheesecake layers are cooled, assemble the cake by layering the lemon blueberry cake, blueberry cheesecake, and frosting.
2. Decorate with lemon wedges and fresh blueberries.