• Preheat your oven to 350°F (177°C).

  Lightly grease cupcake pan with non-stick baking spray, then line it with baking cups.

Make the Lemon Cupcake Batter

• Sift the cake flour, baking powder, and ground ginger together 3 times. Set this dry mixture aside. 

  In a separate pitcher or measuring cup, combine the buttermilk and vanilla extract. Set this aside.
• In a mixing bowl or the bowl of a stand mixer, blend together the unsalted butter, sugar, lemon zest, and kosher salt on medium speed for 1 minute.

  Stop the mixer and scrape down the bowl and paddle. Begin mixing the butter-sugar mixture again, this time on medium-high speed for 3 minutes. Stop the mixer and scrape down the bowl and beater once during the mixing time.
• Add the eggs to the mixing bowl- one at a time- mixing for 30 seconds. Stop the mixer and scrape the bowl down after you add each egg.

  Once both eggs have been added, increase the speed to medium-high and whip the mixture until it looks light and airy, this should take about 4 minutes. Stop the mixer 2 times to scrape down the bowl and beater.
• Add a third of the flour to the mixer's bowl and mix on low speed just until the flour is incorporated.

  Next, add half of the buttermilk and mix for a 20 seconds at low speed.

  Stop the mixer and scrape down the bowl and beaters.

  Repeat the 1/3 flour-remaining milk-remaining flour cycle, making sure to scrape down the bowl after adding the milk, and one final time after the last addition of flour.
• Finish mixing the batter by hand using a rubber spatula to fold the batter 10 times.

Bake the Lemon Cupcakes and Make the Simple Syrup

• Once the batter is smooth, use a #16 (or a 1/4 measuring cup) portion scoop to fill each cavity of your cupcake pan 2/3rds full of batter. 

  Bake the cupcakes for 18 minutes, or until they're golden and their tops spring back when lightly pressed.
• Make the lemon simple syrup while the cupcakes are baking.

  In a small bowl, stir together the reserved 1 1/2 tablespoons of lemon juice (from the lemon you zested) and 1 1/2 tablespoons of sugar. Microwave this mixture on high for 15-20 seconds.

  Once it boils, pull it out of the microwave and stir to dissolve the sugar.
• Once the cupcakes are baked, remove their pan from the oven and brush two layers of the lemon simple syrup over the cupcakes. 

  After the cupcakes are brushed, allow them to cool in the pan for 5 minutes to allow them time to set up. Transfer the cupcakes to a cooling rack and allow them to cool completely.

Fill the Lemon Cupcakes with the Lemon Curd

• Press an apple corer (or cookie cutter) into the center of a completely cool cupcake.

  After removing the middle, use your finger to press down any remaining cake in the center of the cupcake. This helps form a barrier between the paper liner and the lemon curd.
• Spoon a tablespoon of the Meyer lemon curd into the hole you made in the cupcake.

  Gently tap the cupcake to settle the curd a bit adding a little more curd if there's a divot in the filling.
• Continue removing and filling the cupcakes' centers.

  Set the tray of cupcakes aside while you make the Swiss meringue topping.

Make the Swiss Meringue Topping

• Place the egg whites and sugar into a very clean bowl and use a whisk to mix them together for 30 seconds.

  Nestle the bowl onto a 2-quart saucepan filled with a cup of water.

  Heat the egg whites and sugar in a double boiler constantly stirring, over medium heat until the whites reach 160°F (71°C) when measured by a candy thermometer (or until really warm to the touch).
• Add the cream of tartar to the warm egg whites and begin whipping the mixture with the whisk attachment of your electric mixer at medium speed.

  Once the egg whites look foamy, increase the speed to high. Whip the egg whites for another 7-8 minutes, or until they stand out in stiff peaks or to the "stiff peak stage."

Decorate and Serve the Lemon Meringue Cupcakes

• Once the Swiss meringue is ready, fit a piping bag with a 1M (large star tip) or 809 (plain round tip).

  Gently fill the piping bag with the Swiss meringue.
• Pipe a mound of Swiss meringue onto each cupcake, making sure to cover the lemon meringue filling.
• Ignite your butane torch so the flame is about 3 inches from the stem of the torch (or set it to medium flame).

  Toast the exterior of the piped Swiss meringue to a deep golden brown.
• Serve the Lemon Meringue Cupcakes as is or decorated with fresh lemon slices.

  Enjoy the Lemon Meringue Cupcakes within 2 days of decorating. Store leftovers in the refrigerated in an uncovered container.