Preheat your oven to 350°F (175°C). Grease and line three 8-inch round cake pans with parchment paper.

In a medium bowl, sift together the cake flour, baking powder, and salt three times. Set aside.

In a stand mixer fitted with the paddle attachment, cream the softened butter, granulated sugar, and lemon zest on medium-high speed for 4-5 minutes until light and fluffy.

Add the room temperature eggs one at a time, mixing well after each addition. Mix in the pure lemon extract.

In a separate cup, stir the sour cream and whole milk together. Alternately add the dry flour mixture and the wet milk mixture to the batter in 3 batches, beginning and ending with the dry ingredients. Mix strictly until just combined.

Gently toss the fresh raspberries in one tablespoon of dry flour. Carefully fold the flour-dusted berries into the cake batter by hand using a spatula.

Divide the batter evenly among the three prepared pans. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Allow layers to cool completely before assembling.

To make the filling: In a saucepan over medium heat, simmer the raspberries, sugar, and lemon juice for 5 minutes until the berries break down. Stir in the cornstarch slurry and simmer for 1 more minute until thickened into a glossy coulis. Cool completely in the fridge.

To make the frosting: Beat the soft cream cheese and butter together for 2 minutes until perfectly smooth. Gradually add the powdered sugar, lemon juice, and zest, beating until light and fluffy.

To assemble: Place the first cake layer down. Pipe a sturdy 1/2-inch thick ring dam of frosting around the perimeter of the layer. Spread half of the chilled raspberry filling inside that dam. Repeat with the second layer. Top with the final layer and frost the outside of the cake.