Prepare two baking sheets by lining them with parchment paper or silicone baking mats.
Sift almond flour, powdered sugar, and freeze dried raspberry powder through a fine mesh sieve into a bowl. Repeat one more time to make sure the ingredients are uniformly combined, discarding any larger pieces that don't go through the mesh sieve. Set aside.
3/4 cup almond flour/meal, 1/2 cup powdered sugar, 1/4 cup freeze dried raspberries
In a large bowl, beat the egg whites on medium speed until frothy, about 1 minute, then slowly add the granulated sugar, about 1 tablespoon every 20 seconds or so. Increase the speed to medium-high then continue to beat until stiff peaks form.
3 large egg whites, 1/2 cup granulated sugar
Fold the sifted almond mixture into the egg whites using a spatula until the batter becomes the consistency of lava and drizzles off a spatula in a thick ribbon.
Transfer the macaron batter to a piping bag fitted with a large round tip or a ziploc bag with one corner cut off. Pipe the macaron batter in 1 1/2-inch circles onto the silpat mat or parchment paper lined baking sheets. Let the macarons sit for 30-60 minutes until the top is dry enough to touch. It may take even longer if the day is humid.
Preheat oven to 300°F. Bake one sheet of macaron shells at a time for 16-18 minutes. Cool completely on the baking sheet before attempting to remove the macaron shells from the pan.
Meanwhile, make the raspberry buttercream by beating the butter in a medium bowl until creamy and smooth. Add the powdered sugar and jam and mix again. Add as much heavy cream as needed to get a good piping consistency.
1/4 cup salted butter, 1 cup powdered sugar, 3 Tablespoons raspberry jam, 1-2 teaspoons heavy cream
To fill the macaron shells, transfer the raspberry buttercream to a bag fitted with a small round tip or a ziploc bag with one corner cut off. Pipe a border of buttercream around the edges of half of the macaron shells. Fill with 1/2 teaspoon of raspberry jam, then top with another macaron shell.