Preheat oven to 350°F. Line a 12-cup muffin pan with paper liners and set out a second pan or extra liners for about 15 cupcakes. Bring butter, eggs, sour cream, and milk to room temperature.
In a medium bowl, whisk together cake flour, baking powder, and salt. Set aside.
In a stand mixer or large bowl with a hand mixer, beat softened butter and granulated sugar on medium speed for 2-3 minutes until pale and fluffy.
Add eggs one at a time, beating well after each addition. Mix in vanilla extract, lemon extract, lemon zest, and lemon juice until combined. Scrape down the bowl as needed.
Combine sour cream and milk in a small bowl. With mixer on low, add flour mixture in three additions, alternating with sour cream mixture, starting and ending with flour. Mix just until combined, being careful not to overmix.
Toss fresh raspberries with 1 tablespoon flour, then gently fold them into the batter with a spatula, taking care not to crush the berries.
Use a cookie scoop to divide batter evenly among cupcake liners, filling each about two-thirds full. Bake for 18-20 minutes until a toothpick inserted in the center comes out clean. Cool in pan for 5 minutes, then transfer to a wire rack to cool completely.
In a large mixing bowl, beat softened butter until smooth and creamy. Add powdered sugar in two additions, beating well after each. Mix in raspberry preserves, lemon juice, and a pinch of salt. Add heavy cream one tablespoon at a time until frosting reaches a smooth, pipeable consistency.
Transfer frosting to a piping bag fitted with your favorite tip and pipe swirls onto fully cooled cupcakes. Top with a fresh raspberry and a light sprinkle of lemon zest.