Preheat oven to 350 degrees (F). Cut out two 9-inch round segments of parchment paper to line your cake pans with. Spray each pan generously - sides and bottom - with nonstick cooking spray, then place the parchment paper cut out in the bottom of the pans and spray again. It's important to make sure every bit of pan and paper are sprayed so your cakes don't get stuck. Set pans aside.

In a large bowl using a handheld electric mixer (or in the bowl of a stand mixer fitted with the paddle attachment), combine the butter, both sugars, lemon zest, lemon extract, and vanilla extract; beat on medium speed, scraping down the sides of the bowl as needed, until light and fluffy, about 5 minutes.

Add in the eggs, one at a time, beating well after each addition, and scraping down the sides of the bowl as needed. Set aside.

In a separate bowl, whisk together the cake flour, baking powder, baking soda and salt, mixing well to evenly combine the ingredients. Add the dry mixture into the wet ingredients and mix on low speed until everything is just barely combined.

Turn mixer off. Add in the milk, sour cream, and lemon juice; use a rubber spatula to fold the ingredients into the mixture, stirring until everything is incorporated, but being sure not to overmix. Set aside.

In another bowl, gently toss the raspberries with 2 tablespoons of all-purpose flour. Add the raspberries, and any remaining flour, to the batter and fold in by hand, using a rubber spatula, until just combined.

Divide the batter evenly among the prepared pans and bake for 35 to 40 minutes, or until the tops are firm and slightly golden, and a cake tester (or toothpick) inserted in the center comes out clean, or with a few moist (but not wet) crumbs clinging to it.

Allow the cakes to cool in the pans for 10 minutes before gently running a knife around the edges to loosen any stuck bits, then turning them out onto a cooling rack to cool completely.

In a large bowl using a handheld electric mixer (or a stand mixer fitted with the paddle attachment) beat the cream cheese and butter on medium-speed until light and fluffy, about 3 minutes, scraping down the sides of the bowl as needed.

Reduce the speed to low and gradually add in the confectioners' sugar. Add in lemon zest, lemon juice, lemon extract, and salt; beat until combined.

Increase the speed back to medium and mix until creamy, about 2 minutes. Add the sour cream and continue beating the frosting until very light and fluffy, about 2-3 minutes.

If the frosting seems too thin, add a little more confectioners' sugar, starting with one tablespoon at a time; if the frosting seems to thick, add in a little more sour cream, starting one tablespoon at a time.

When the cakes have completely cooled, place one round on a cake stand or large plate; spread the top and sides evenly with frosting, then top with the raspberry preserves.

Gently place the other cake round on top of the frosted one and press down very lightly to seal them together. Place the semi-frosted cake in the fridge for 20 minutes, then continue frosting the cake until the top and sides are evenly frosted.

Place the cake back in the fridge for another 20 minutes before decorating. Decorate with fresh raspberries and thin lemon slices, or according to your own tastes.

The frosted cake will stay fresh, covered and stored in the refrigerator, for 3 days. Simply take it out of the fridge an hour or two before serving so it can come to room temperature.