Dulce De Leche Macarons

Things have been pretty hectic for me as of late. I've been baking more than ever- just not posting about it!
Since Cinco de Mayo is right around the corner, I wanted to share these Dulce de Leche french macarons with you. I made my dulce de leche from scratch, but you can also buy it.
For the Macaron Shells (makes about 35 cookie shells)
Ingredients
3/4 cup almond flour
1 cup confectioner's sugar
1/4 cup granulated sugar
2 egg whites (separated and left on the counter for at least 24 hours)
Small pinch cream of tartar
A few drops of gold and one drop of orange food coloring


Directions:
Preheat oven to 275 degrees. Sift almond flour and confectioner's sugar 2 times. Set aside. Whisk egg whites on low-medium until foamy. Add a small pinch of cream of tartar. Whisk on medium-high until whites are whipped and have soft peaks. Slowly add in 1/4 cup sugar and food coloring, continuously whisking until whites form stiff peaks.

TIP: Whites should form a peak on the whisk attachment, but should not be whisked to the point that they are too stiff to fall off the whisk when tapped on the mixing bowl.

Sift dry ingredients over egg whites in three parts- do not stir, but fold gently with a rubber spatula into egg whites. Continue folding batter until it "ribbons" off rubber spatula. Scoop batter into a 14-16 inch pastry bag fitted with a medium round tip. Pipe circles onto parchment paper lined baking sheets (or use silpat). After piping, hit baking sheet on the counter a few times to remove air bubbles. Allow cookies to sit for 15-30 minutes before baking so that they form a protective "skin." This step also helps to avoid cracking. Allow shells to fully cool before filling.
For best taste, allow macarons to meld with filling at least overnight and preferably 1-2 days.


For the Dulce de Leche filling:
Combine a generous cup of dulce de leche with 3/4 stick butter in bowl of stand mixer.
Using whisk attachment, beat on high until mixture is combined and is a whipped consistency.
 Using a pastry bag, pipe a small amount of filling on one side of each cookie and sandwich together