Preheat oven to 325°F (163°C). Line a 9-inch springform pan with parchment paper.
In a stand mixer, beat 16 oz cream cheese and 1/2 cup sugar until smooth. Incorporate 2 eggs, sour cream, and 1 tsp lemon zest.
Fold in fresh blueberries. Pour into the prepared pan and bake for 50 minutes. Cool to room temperature, then freeze for 4 hours to firm.
Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans.
Sift flour, baking powder, and salt. In a separate bowl, cream 3/4 cup butter and 1 cup sugar until light and fluffy.
Add 3 eggs one at a time to the butter mixture, then stir in remaining lemon zest, lemon juice, and milk.
Gradually fold the dry ingredients into the wet ingredients until just combined.
Divide batter between the two cake pans and bake for 28-32 minutes. Cool completely on wire racks.
Prepare frosting by beating 8 oz cream cheese, 1/2 cup butter, powdered sugar, and blueberry preserves until light and airy.
Place one cake layer on a serving plate. Place the frozen cheesecake layer on top. Place the second cake layer on the cheesecake.
Apply a thin crumb coat of frosting, refrigerate for 30 minutes, then apply the remaining frosting to the top and sides.
Refrigerate the assembled cake for at least 4 hours before slicing to ensure structural integrity.