Prepare the Cake Layers: Preheat oven to 350°F. Grease and flour 2 (8-inch) round cake pans. Beat butter with a stand mixer fitted with a paddle attachment on medium speed until creamy, about 1 minute. Gradually add sugar, beating until light and fluffy, 3 to 4 minutes. Beat in lemon zest. Add eggs 1 at a time, beating until just blended after each addition.

Whisk together flour, baking powder, and salt in a bowl. Add flour mixture to butter mixture alternately with sour cream, beginning and ending with flour mixture, beating on low speed until just blended after each addition. Beat in lemon juice. Divide batter evenly between prepared pans; spread evenly in pans.

Bake in preheated oven until a wooden pick inserted in centers of cakes comes out clean, 22 to 26 minutes. Let cool in pans on wire racks 10 minutes. Remove cakes from pans, and let cool completely on wire racks, about 1 hour.

Prepare the Frosting: Process 1/2 cup raspberries in a blender or food processor until completely smooth, about 1 minute. Spoon pureed raspberries into a fine mesh strainer set over a small bowl; press raspberries using the back of a spoon to strain juices. Set raspberry juice aside. Discard solids.

Beat cream cheese and 6 tablespoons of the sugar with a heavy-duty stand mixer fitted with a paddle attachment on medium speed until smooth, about 2 minutes. Add 2 tablespoons raspberry juice; beat until combined. (Discard remaining raspberry juice, or reserve for another use.)

Beat whipping cream and lemon juice with an electric mixer fitted with a whisk attachment on medium speed until foamy, about 30 seconds. Increase speed to medium-high; slowly add remaining 6 tablespoons sugar, beating until stiff peaks form, about 5 minutes. Fold half of the whipped cream mixture into cream cheese mixture; fold in remaining whipped cream mixture.

Assemble the cake: Place 1 Cake Layer on a serving plate or a cake stand; spread with some of the Frosting to a 1/2-inch depth. Cover frosted Cake Layer with 1 1/2 cups raspberries, flat sides down, leaving a 1/2-inch border. Spread some of the frosting over raspberry layer to a depth of 1/2 inch. Top with remaining Cake Layer. Spread remaining Frosting over top and sides of cake. Decorate with whole or halved raspberries.