Yield: about 2 dozen cupcakes

Ingredients

For the cupcakes:
1¾ cups all-purpose flour
1 tsp. baking powder
½ tsp. baking soda
½ tsp. salt
1¼ cups (8 oz.) sugar
Zest of 1 large lemon, preferably organic
1 cup (2 sticks) unsalted butter, at room temperature
3 large eggs, at room temperature
½ cup sour cream
¼ cup milk
Juice of 1 large lemon

For the filling:
16 oz. raspberries (fresh or frozen)
¼ cup sugar
1 tbsp. water
1 tbsp. cornstarch
Squeeze of lemon juice

For the frosting: 
3 large egg whites
½ cup sugar
1 cup (2 sticks) unsalted butter, at room temperature
Pinch of salt
2-3 tbsp. fresh raspberry puree*
Zest of 1 lemon
Candied lemon slices, for garnish
Fresh raspberries, for garnish

  • step 1: HideShow Images

    To make the cupcakes, preheat the oven to 350˚ F.  Line cupcake pans with paper liners.  In a medium bowl, combine the flour, baking powder, baking soda and salt.  Whisk to blend.  In the bowl of an electric mixer, combine the sugar and lemon zest.  Mix for about 1 minute on low speed to infuse the sugar with the lemon scent.  The sugar should have the appearance of wet sand.  Add in the butter and beat on medium-high speed until light and fluffy, about 2 minutes.  Beat in the eggs one at a time, scraping down the bowl after each addition.  In a liquid measuring cup, combine the sour cream, milk and lemon juice.  Whisk to blend.  With the mixer on low speed, add the dry ingredients in three additions alternating with the wet ingredients, beginning and ending with the dry ingredients.  Mix each addition just until incorporated.

  • step 2: HideShow Images

    Divide the batter between the prepared cupcake liners filling each about ¾-full.  Bake, rotating the pans halfway through baking, 18-20 minutes or until a toothpick inserted in the center comes out clean.  Let cool in the pan briefly, then transfer to a wire rack to cool completely before proceeding.

  • step 3: HideShow Images

    To make the filling, combine the raspberries and sugar in a medium saucepan over medium heat, stirring occasionally.  Combine the water and cornstarch in a small bowl and whisk until smooth.  Once the berries and their juices begin to bubble, stir in the cornstarch mixture.  Bring to a boil and let boil until slightly thickened, about 1-2 minutes more.  Remove from the heat and stir in the lemon juice.  If desired, strain through a fine mesh sieve to remove the raspberry seeds (optional).  Once the filling is cool, use the cone method to fill the cupcakes with about 2 teaspoons of filling each.

  • step 4: HideShow Images

    To make the frosting, combine the egg whites, sugar and salt in a heatproof bowl set over a pot of simmering water.  Heat, whisking frequently, until the mixture reaches 160° F and the sugar has dissolved.  Transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment.  Beat on medium-high speed until stiff peaks form and the mixture has cooled to room temperature, about 8 minutes.   Reduce the speed to medium and add the butter, 2 tablespoons at a time, adding more once each addition has been incorporated.  If the frosting looks soupy or curdled, continue to beat on medium-high speed until thick and smooth again, about 3-5 minutes more (don’t worry, it will come together!  This can sometimes take a very long time.)

  • step 5: HideShow Images

    Divide the finished frosting into two separate bowls.  To one of the bowls, add the fresh raspberry puree and mix to incorporate.  To the other, mix in the lemon zest.  Fit a pastry bag with a large decorative tip (I used a large, unlabeled closed star tip.)  Fill one side of the pastry bag with the raspberry frosting, and then fill in the other side with the lemon frosting (this does not need to be exact – just enough so that both colors are included.)  Pipe a test streak until you see both colors coming out of the tip.  Frost cupcakes as desired, refilling the pastry bag in the same manner as needed.  Garnish the finished cupcakes with candied lemon slices and/or fresh raspberries, if desired.

  • step 6: HideShow Images

    *To make raspberry puree, simply add fresh or frozen raspberries to a blender or food processor and blend until smooth.  Strain to remove the seeds.  From 6 ounces of fresh berries you will get about ½ cup of puree.