For the lemon cupcakes:

• 2 1/3 cups cake flour
• 2 3/4 tsp baking powder
• 1/4 tsp salt
• 5 large egg whites, at room temperature
• 1/4 tsp cream of tartar
• 1 1/2 cups sugar
• 2 tbsp finely grated lemon zest
• 12 tbsp unsalted butter, at room temperature
• 1 cup whole milk
• To make the cupcakes: Position a rack in the middle of the oven and preheat the oven to 350 degrees F.  Line two 12-cup cupcake pans with cupcake liners.
• Whisk together the flour, baking powder, and salt in a bowl; set aside.   In the clean, dry bowl of an electric mixer fitted with the whisk attachment, beat the egg whites on medium speed until foamy.  Add the cream of tartar and increase the speed to medium-high.  Beat just until stiff peaks form when the whisk is lifted.  Transfer the egg whites to a separate bowl (not plastic), clean  and dry the mixer bowl and reattach it with the paddle attachment.
• Add the butter to the mixer bowl and beat on medium speed until smooth.  Gradually add the sugar and beat until incorporated.  Mix in the lemon zest.  Beat the mixture on medium-high speed until light and fluffy.  Beat in 1/4 cup of the milk until just blended.  Reduce the speed to low and add the flour mixture alternately with the remaining milk in three batches, beginning and ending with the flour; scrape down the sides of the bowl as necessary.  Beat until just blended.  Using a rubber spatula, fold one quarter of the egg whites into the batter, being careful not to deflate the mixture.  Once incorporated, add in the rest of the whites (including any liquid that may have accumulated on the bottom of the bowl) and gently fold in until well combined; no white should remain.
• Using a large cookie/ice cream scoop, divide the batter between the cupcake liners, filling each liner about 2/3 full. Bake until golden and a toothpick inserted in the center comes out clean, about 18-22 minutes, turning the pans around halfway through the baking time.  Cool the cupcakes in the pan on a wire rack for 5 minutes then remove them from the pans and cool completely on a wire rack.  Allow the cupcakes to cool completely.
• Once the cupcakes have cooled, hollow out the center of each cupcake using the cone method and spoon about 1 tsp of raspberry curd in to each hollowed-out cupcake.  The filling should be just shy of the top of the cupcake.  Frost as desired, taking care not to push the curd out of the cupcake with the weight of the frosting.  

For the lemon buttercream frosting:

• 16 tbsp unsalted butter, at room temperature
• 2 tbsp finely grated lemon zest
• 3 cups confectioners’ sugar, sifted
• 2 tbsp heavy cream
• 1 tbsp fresh lemon juice

 To make the frosting: In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and zest on medium speed until light and fluffy.  Gradually add the sugar and beat until smooth.  Add the heavy cream and lemon juice and beat for one minute longer; the frosting should be light and fluffy.

 Lemon Curd

Ingredients

• 5 egg yolks
• 1 cup sugar
• 4 lemons, zested and juiced
• 1 stick butter, cut into pats and chilled

Directions