Blood Orange Curd

1. In a small saucepan, whisk together the blood orange juice, zest, egg yolks and sugar.  Cook over a medium heat, stirring continuously, until the mixture is thick enough to coat the back of a wooden spoon, or until it reaches a temperature of 160°F.
2. Remove from the heat and strain the curd through a fine mesh sieve into a clean bowl.  Add in the diced butter and whisk until butter is fully incorporated.  Cover curd with plastic wrap, pressing it directly against the top of the curd to prevent a skin from forming.  Refrigerate for at least 4 hours or overnight, until the curd is fully set. 

Macaron Shells

1. Line 3 baking sheets with parchment paper or silicone baking mats.  If desired, place a template under the parchment paper with 1 1/4 – 1 1/2 inch diameter circles to use as a piping guide.
2. Sift together the almond flour and confectioners sugar into a large bowl, discarding any large granules that remain in the sieve.  Gently whisk to combine.  Add in the first portion of egg whites (55 grams) to the bowl.  Use a rubber spatula to mix egg whites into the dry ingredients to form a paste.  (It might seem like there is not enough liquid to coat all of the dry ingredients, but keep mixing and a thick paste will form.)
3. In a small saucepan, add in the granulated sugar and water.  Gently stir to moisten all of the sugar.  Use a candy thermometer to measure the temperature of the sugar mixture closely while cooking.  Begin heating over a medium high heat and bring to a boil.  (As the syrup boils it may splatter onto the sides of the pan.  Use a damp pastry brush to gently wipe any splatters back into the syrup.  This will help prevent crystallization.)
4. When the sugar syrup reaches 240°F add the second portion of egg whites (55 grams) to the bowl of a stand mixer fitted with the whisk attachment.  Begin whisking the egg whites on a medium – high speed until frothy.  Once the sugar syrup reaches 244°F reduce the mixer to low speed and very carefully add in the hot syrup into the egg whites in a slow stream.  Avoid hitting the whisk when adding the syrup to prevent it from splattering around the sides of the bowl.
5. Once all the syrup is added increase the speed to high and whisk for 3-4 minutes, until the egg whites begin to form soft peaks.  At this point, stop the mixer and add in the vanilla extract.  You can also add in gel food coloring at this point, but only if you are making the shells one color. (*See note below for how to make two-toned macarons.)  Continue whipping the egg whites for a few more minutes until they are thick, glossy and form stiff peaks (do not over beat).  The meringue should have cooled down to room temperature. 
6. Take a large spatula full of the meringue and add it into the almond-sugar paste.  Fold the meringue into the paste to begin to loosen the consistency.  Add in the remaining meringue and continue folding into the batter, sweeping the spatula around the outside of the bowl and then cutting through the middle to combine.  Keep mixing until the batter falls off the spatula in a “ribbon” and moves like slow lava.  You should be able to draw a figure “8” with the batter as if falls off the spatula.  The “ribbon” should smooth itself back into the bowl of batter after about 10 seconds.  This is when the batter is ready to pipe.
7. Transfer the batter to a large piping bag fitted with a medium sized round tip.  Secure the end of the piping bag with a bag clip or a rubber band to prevent the batter from spilling out of the top.  Onto the prepared baking sheet, pipe batter into even circles, about 1 1/4 – 1 1/2 inch in diameter, leaving about an inch spacing between each circle.  Gently but firmly tap the baking sheet on your work surface a few times to release any air bubbles from the piped macarons.  Pop any stubborn air bubbles gently with a toothpick.
8. Let the piped macarons sit on the counter for 30-60 minutes to dry out and form a skin.  Or until they no longer feel sticky when touched.  This is when they are ready to bake. 
9. Preheat the oven to 325°F.  Bake one sheet at a time for 10-12 minutes.  Macarons are done when the tops are set and there is little to no jiggle from the “feet” when lightly touched.  Let macarons cool completely before removing from the baking sheet. 

Blood Orange Buttercream

1. In a stand mixer fitted with the paddle attachment, beat the butter until light and creamy.  Add in the sifted confectioners sugar and continue mixing until fluffy, scraping down the sides and bottom of the bowl as needed.
2. Add in the blood orange zest and 3 tsp blood orange juice.  Beat together for 1 minute.  If buttercream is too thick add in an additional tsp of blood orange juice.  Beat on a medium to high speed for a few more minutes until everything is well mixed and the buttercream is light and fluffy.
3. Place buttercream into a piping bag fitted with a medium round tip.

Assembly

1. Match up pairs of similarly sized macaron shells.  On one flat side pipe a ring of buttercream, leaving a hole in the middle.  This will create a dam to hold in the curd.
2. Dollop about 1/2 tsp or so of the blood orange curd into the center of the buttercream dam.  Place the second macaron on top of the filling and press together gently to adhere.
3. Allow filled macarons to rest in the fridge for a few hours or overnight for the best results.  The meringue cookie will meld with the filling and create a soft chewy center while keeping the crisp outer shell.
4. Let sit at room temperature for 15 minutes before serving.  Store macarons covered tightly with plastic wrap or in an airtight container in the fridge.