Prep: Preheat your oven to 350°F. Prepare two 9-inch round cake pans by lining them with parchment paper and greasing them with nonstick spray to prevent sticking.
Cake Batter (Wet Ingredients): In a large bowl, cream together the unsalted butter, granulated sugar, light brown sugar, lemon zest, lemon extract, and vanilla extract. Beat until light and fluffy, which should take about 5 minutes. Then, add the eggs one at a time, making sure each one is fully incorporated.
Cake Batter (Dry Ingredients): In another bowl, whisk together the cake flour, baking powder, baking soda, and salt. This will ensure your dry ingredients are evenly mixed.
Combine Batter: Gradually add the dry ingredients to the wet mixture while mixing on low speed. Once just combined, gently mix in the milk, sour cream, and fresh lemon juice for that delightful tang.
Incorporate Raspberries: Toss the fresh or frozen raspberries in some all-purpose flour to keep them from sinking. Gently fold them into the batter by hand until just combined; be careful not to overmix!
Bake: Divide the batter evenly between your prepared pans and bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
Cool Cakes: Allow the cakes to cool in their pans for about 10 minutes before transferring them to a wire rack. Let them cool completely.
Make Frosting: In a mixing bowl, beat the cream cheese and butter together until fluffy. Gradually add in the confectioners' sugar, lemon zest, lemon juice, lemon extract, and salt. Beat until smooth, then mix in sour cream until the frosting is light and fluffy.
Assemble and Frost: Place one cooled cake layer on a serving plate. Spread a layer of frosting on top, then add a layer of raspberry preserves. Place the second cake layer on top, pressing down gently. Chill in the fridge for 20 minutes, then frost the entire cake. Chill again for another 20 minutes and finish off with fresh raspberries and lemon slices for garnish.
Serve: Your stunning Lemon Raspberry Cake is ready to be enjoyed! Keep it covered in the refrigerator, and it will stay fresh for up to 3 days. Bring it to room temperature an hour or two before serving for the best taste.