friday is upon us.  let’s celebrate with cupcakes!yummy, summery lemon cupcakes, filled with lemon curd & topped with lemon swiss buttercream frosting.

the lemon cupcake & lemon curd recipe come from martha stewart, but hi, martha?  you’re forgetting something.  frosting. i don’t believe in cupcakes without frosting, especially birthday cupcakes for a friend who’s had a hell of a year & deserves to thoroughly enjoy herself.

so, i took it upon myself to add my newest favorite icing.

this recipe comes in three parts, but they’re each 100% worth it.

LEMON CURD
slightly adapted from martha stewart living (makes 2 cups)

2 whole eggs, plus 8 egg yolks (save the whites! you’ll use them for frosting.)
1 cup sugar
2/3 cup fresh lemon juice (about 4 lemons)
2 tablespoons unsalted butter, cut into small pieces, room temperature

1. set up your double boiler. ::ahem:: pot of simmering water & pyrex bowl. combine the eggs, yolks, sugar & lemon juice in the bowl and set over simmering water. cook, whisking constantly, until it thickens enough to coat the back of a spoon.  at this point, the foam will noticeably subside & you’ll have a nice, thick custard.

2. remove from heat & add butter, a few pieces at a time, whisking the mixture after each addition.

3. strain through a sieve, or fine mesh strainer, into another bowl. cover with plastic wrap, allowing the plastic to touch the entire top surface of the curd. it will prevent it from getting that thick skin on top. refrigerate until chilled & firm….until the cupcakes are ready!

LEMON CUPCAKES
very slightly adapted from martha stewart living (makes 24 cupcakes)

1 3/4 cups flour
1 tablespoon freshly grated lemon zest
1/4 teaspoon baking powder
3/4 teaspoon kosher salt
7/8 cup (1 3/4 sticks) unsalted butter, at room temperature
1 1/2 cups sugar
4oz cream cheese, at room temperature
4 large eggs, at room temperature
1/2 teaspoon vanilla
2 tablespoons lemon juice

1. preheat oven to 325°.  line cupcake pans with liners.  whisk together flour, zest, baking powder & salt.  set aside.

2.  in the bowl of a stand mixer, cream butter & sugar on medium high, until they lighten in color & get fluffy.  beat in the cream cheese.  mmmmm.  reduce speed to low.  add the eggs, one at a time, beating until each one is mixed in.  stop & scrape down the sides, if you think it’s necessary.  beat in the lemon juice & vanilla.  now it’s time for the dry ingredients.  add the flour, still beating on low, in three batches.  stir each addition until just combined, no more.

3.  fill the cupcake liners 3/4 the way up.  bake for about 28 minutes, rotating the pans halfway through, until a toothpick comes out clean.  transfer to cooling racks & let cool completely.

LEMON SWISS MERINGUE BUTTERCREAM
2 cups sugar
8 egg whites (see! this is meant to be!)
1 1/2 cups (3 sticks) unsalted butter, at room temperature
5 tablespoons lemon juice

1. get the double boiler set up going again. in the pyrex bowl, combine the sugar & egg whites with a whisk. set over simmering water & whisk frequently until a candy thermometer reaches 160° and the sugar has completely dissolved.

2.  transfer the mixer into the bowl of a stand mixer fitted with the whisk attachment.  beat on medium high until stiff peaks form & the mixture has cooled to room temperature, about 8 minutes, or longer if you’re kitchen is hot, but trust me, it will happen.

3.  reduce the speed to medium & start adding the butter, 2 tablespoons at a time adding more after each addition is fully incorporated.  if the mixture ever starts to look like a hot mess (like a gross, curdled soup), bump the speed back up to medium high until is gets itself back together & looks thick & smooth again.  it might take several minutes.  don’t worry, it happened several times to me, since it was an H-O-T day.  once all the butter has been added, add the lemon juice & beat until thick, fluffy & smooth.