For Macaron Shells

1. Preheat your oven to 300° F. Line two baking pans with parchment or silicone baking mats, and place piping templates underneath the paper. Set up your piping bag with a small round pastry tip, and place it upside down in a sturdy glass, wrapping the open end of the bag around the rim. 
2. If working with whole or slivered almonds: Grind almonds or almond flour with confectioner's sugar in a food processor for a couple of minutes. Stop the processor once or twice to redistribute the mixture. Sift and set aside. 
3. Place the egg whites and granulated sugar in a large bowl or bowl of a stand mixer with a whisk attachment. Whip on medium speed until foamy.
4. Beat, whip, or whisk vigorously to a firm meringue on medium-high speed, for at least five more minutes. The meringue will be shiny and create pointy peaks off of the paddle that curve ever so slightly. 
5. Add a small pinch of orange zest, if using, and beat a few moments more to incorporate it. 
6. Fold the dry ingredients into the batter in a few additions (or all at once if you're confident) until the batter flows slowly and ribbons off the spatula. Mix slightly vigorously at first, then use classic folding strokes; scraping around the sides of the bowl, the up from underneath the mixture, and over through the top. Transfer the batter immediately to your piping bag. 
7. Pipe one to two-inch rounds of batter onto your parchment-lined pans. Hold the piping bag vertically and about a quarter-inch above the pan.
8. To help the tops of the piped batter settle, lightly tap the underneath of the pan a few times. Optional: Let the piped macarons rest on the counter for 15 to 20 minutes. 
9. Bake at 300° F for 14-16 minutes, rotating the pan(s) once halfway through baking.
10. Cool for a few minutes before removing the baked shells from the baking mat or parchment.
11. Fill with the mascarpone buttercream and store chilled. Filled macarons achieve the best texture after maturing in the refrigerator for 24 hours (if you can).

For Mascarpone Buttercream

1. In a medium bowl using a hand mixer, or the bowl of a stand mixer with a paddle attachment, beat cream cheese, butter, and a pinch of salt until smooth and lightened in color, about five minutes.
2. Add powdered sugar in several additions on low speed, beating in each portion completely before adding the next. Stop beating and scrape the bowl as necessary.
3. Once the mixture is smooth and with the mixer off, add the heavy cream or milk, vanilla extract, and orange zest. Then beat briefly to evenly distribute. 
4. Transfer to a piping bag (no tip necessary) or plastic baggie with a corner snipped to make a small opening. 
5. Pipe a small amount on half of the macaron shells, leaving room around the outer edge of the shells (this prevents oozing when you top with the second shell). 
6. Store any extra filling chilled, and bring to room temperature to serve. If necessary, beat the buttercream again briefly before using it after chilling.