Lemon Blueberry Vanilla Bean Cupcake

Lemon Curd filled vanilla bean cupcake, with blueberry swiss meringue frosting. A treat for Grandma P's 91st birthday, these cupcakes would be perfect for any summertime barbeque/pool/garden party. The Blueberry Swiss Meringue is pretty subtle in blueberry flavor. If you would like, add a few drops of blueberry oil to take your cupcake to blueberry heaven.

Lemon Curd
1/2 c. Freshly squeezed lemon juice (about 4 lemons)
3/4 c. White sugar
2 eggs
1 stick unsalted butter, softened and cut into pieces

With your microplane, grate enough lemon zest to measure 2 teaspoons. It is much easier to do this before you juice your lemons. Now, juice your lemons (I love this orange-size juicer). Whisk together zest, lemon juice, sugar and eggs in a metal bowl and add softened butter. Set bowl over a saucepan of simmering water and cook, whisking, until thickened and smooth and an instant-read thermometer registers 160ºF, about 5 minutes. Force curd through a fine sieve set into another bowl.

Serve warm, or let cool slightly and cover the surface of the curd with wax paper until cooled completely. The curd will keep covered and chilled for up to one week.

Please don't hesitate to eat the curd straight from the bowl :)

Blueberry Swiss Meringue Buttercream
5 Egg whites
1 1/4 c. White sugar
2 c. Room temperature unsalted butter (4 sticks or 1lb), cut into very small pieces
1/4 c. + 2 Tbsp Blueberry puree (Instructions to follow)
Pinch of salt

Place sugar and egg whites in the heat-proof bowl of an electric mixer. Set bowl over a pan of gently simmering water, and whisk until sugar has dissolved and egg whites are hot to the touch, about 3 minutes. Test by rubbing the mixture between your fingers; you shouldn't be able to feel any sugar granules. Transfer bowl to mixer stand. Using the whisk attachment, beat on high speed until mixture has almost completely cooled and formed still and glossy peaks, about 8-10 minutes. Stiff peaks should be able to stand without falling over when you lift the whisk straight out of the bowl and turn it upside down (frosting pointing toward the ceiling).

Now to add the butter. If it is truly room temperature, it will be too soft to cut. So using your spatula, scrape no more than 1 tablespoon of butter into the egg mixture at a time. Beat until incorporated after each addition. The buttercream may appear curdled after all the butter has been added; it will become smooth again with continued beating. Add blueberry puree and salt and beat until just combined.

Switch to the paddle attachment, and beat on the lowest speed to eliminate any air pockets, about 5 minutes. If using the buttercream within several hours, cover the bowl with plastic wrap and set aside at room temperature in a cool environment. Or transfer to an airtight container, and store in the refrigerator for up to 3 days. Before using, bring buttercream to room temperature, and beat on the lowest speed with the paddle attachment until smooth, about 5 minutes.

Blueberry Puree
1 lb Blueberries (fresh or frozen)

Bring blueberries to a boil in a sauce pan. Reduce heat to low and simmer until most of the liquid has evaporated—about 1/2 hour—and the mixture is thick, stirring occasionally.

Cool blueberries slightly and transfer to a blender. Mix until smooth. Once pureed, pass the mixture through a fine sieve set into another bowl.

This recipe makes more than you really need. Use the the rest on top of pancakes, waffles, ice cream, meat (or tofu!). Or simmer the leftover with a bit of honey to make a blueberry honey syrup.

To assemble cupcakes:
Make your favorite vanilla (or vanilla bean) cupcakes—I haven't found a favorite yet, any suggestions? I like a dense, but not too dense, super moist cake, with a pronounced vanilla flavor. No luck so far in life.  Anyways, once cooled, using an apple corer or melon baller, scoop about 2–3 tsp of cake out of the center. Don't throw away these insides, that's the best part of the cupcake! Eat them or package them up for a kiddo. Fill holes with the cooled lemon curd using a pastry bag, or by simply snipping the corner of a Ziploc bag filled with curd (I prefer this easy-to-clean-up method). You should have just enough curd to fill the entire batch of cupcakes—with a few extra spoonfuls (for your liking) built in.

Top with a swirl of the blueberry swiss meringue and a fresh blueberry for good measure. You should have enough frosting for one batch of cupcakes with about a cup left over, if frosted like I did in the image above.