for the cupcakes
1 cup butter, at room temperature
2 cups sugar
2 teaspoons grated lemon zest
1 tablespoon lemon extract
3 1/2 cups all-purpose flour
1 teaspoon baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
2 cups sour cream
for the frosting
4 large egg whites
1 1/4 cups sugar
1 1/2 cups (2 sticks) unsalted butter, room temperature, cut into tablespoons
1 teaspoon strawberry extract
1 1/2 cups macerated strawberries, pureed in a food processor
Preheat oven to 350F. Line a mini muffin pan with liners.
In the mixing bowl of your stand mixer, cream butter and sugar. Beat in eggs, one at a time. Add lemon peel and lemon extract; mix well. Combine dry ingredients; add to creamed mixture alternately with sour cream (batter will be thick). Fill cupcake liners 3/4 full and bake for 12-15 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes; remove to wire racks to cool completely.
For the frosting: In the heatproof bowl of an electric mixer set over a saucepan of simmering water, combine egg whites and sugar. Cook, whisking constantly, until sugar has dissolved and mixture is warm to the touch, but not hot. Attach the bowl to the mixer fitted with the whisk attachment. Beat the egg-white mixture on high speed until it holds stiff peaks. Continue beating until the mixture is fluffy and cooled, about 6 minutes. Switch to the paddle attachment. With mixer on medium-low speed, add butter several tablespoons at a time, beating well after each addition. (If frosting appears to separate after all the butter has been added, beat on medium-high speed until smooth again, 3 to 5 minutes more.) Beat in strawberry extract. Beat on lowest speed to eliminate any air bubbles, about 2 minutes. Stir in macerated strawberries with a rubber spatula until frosting is smooth.
Decorate cupcakes as you desire, in this case, with an additional small fresh strawberry.