Preheat your oven to 350 degrees. This is crucial to ensure even baking and a nice rise for your cupcakes.
In a mixing bowl, sift together all-purpose flour and cake flour. Then, add baking powder, baking soda, and salt. Whisk everything together for about 20 seconds to ensure even distribution, then set it aside.
In a food processor, pulse together granulated sugar and lemon zest until finely ground. This should take about 1 minute. The result will have a lovely citrus aroma, setting the stage for what’s to come!
In the bowl of an electric stand mixer fitted with the paddle attachment, cream together unsalted butter and the lemon sugar mixture until pale and fluffy. Make sure to scrape the sides of the bowl to incorporate everything evenly.
Add in one large egg, mixing well, followed by the egg whites one at a time. Add the vanilla extract and lemon extract (if using) with the second egg white for extra flavor.
In a separate liquid measuring cup, whisk together buttermilk and fresh lemon juice. This combination will add moisture and tang.
Gradually add in the flour mixture in three parts, alternating with the buttermilk mixture. Start and end with the flour mixture, mixing just until combined after each addition. Be careful not to overmix; we’re aiming for a tender cupcake!
Divide the batter evenly among 12 lined muffin cups. Each cup should be about two-thirds full. This allows room for the cupcakes to rise.
Bake in your preheated oven for about 18 to 20 minutes. Check for doneness by inserting a toothpick into the center; it should come out clean.
Once baked, remove the cupcakes from the oven and let them cool in the tin for several minutes. Afterward, transfer them to a wire rack to cool completely.
Meanwhile, prepare the simple syrup by whisking together lemon juice and granulated sugar in a small bowl until the sugar dissolves. Brush this mixture over the warm cupcakes for a delightful glaze.
For the frosting, puree fresh raspberries in a food processor until smooth. Strain through a fine mesh strainer to remove seeds, aiming for 6 to 7 tablespoons of puree. Heat this mixture in a saucepan over medium-low heat until reduced by half, then cool completely.
In the stand mixer, whip unsalted butter until pale and fluffy. Gradually mix in 1 cup of powdered sugar, then add the cooled raspberry puree and vanilla extract. Add the remaining powdered sugar until the frosting is light and fluffy.
Finally, add a raspberry to the top of each cupcake and pipe the frosting over it. Top with another raspberry and a small lemon wedge for garnish. Enjoy your gorgeous creations!
