For macarons: Heat oven to 300 degrees. Line 2 baking sheets with silicone baking mats or parchment paper. Fit a large pastry bag with a 1/4” round tip. Set a second pastry bag for ganache aside. Add powdered sugar, almond flour, and Reunion Island Pink Peppercorns to a large food processor (or a smaller one in batches) and pulse for 20 seconds. Add almond flour mixture to a sifter and sift 3 times, going back and forth between two mixing bowls and pushing all of the mixture through sifter with a rubber spatula each time. If larger pieces of peppercorn are not going through sifter, return pieces to mortar and pestle and grind until most go through.
Add egg whites to bowl of stand mixer fitted with the whisk attachment and mix on medium-low, adding cream of tartar when egg whites begin to foam. Turn mixing speed up to medium and slowly add granulated sugar when egg whites are opaque, about 2 to 3 min. into mixing. Add a few drops of pink gel food coloring, if desired. Continue mixing until you just begin to reach glossy and stiff but still flexible peaks. Add half of the sifted dry ingredients to whipped egg whites and fold in gently with rubber spatula. Add second half of the dry ingredients and continue to fold until batter flows like lava without breaking when spatula is raised.
Add batter to pastry bag, leaving enough room at the top to twist the bag and trap batter. Pipe identical 1” rounds, leaving 1 1/2” spaces between each cookie. When finished piping, immediately lift baking sheet out in front of you with straight arms and drop flat onto the counter. Repeat twice more to bring any air bubbles to the surface. Use toothpick to pop any visible air bubbles. Leave piped cookies on the counter uncovered for 20 to 30 min., or until a skin forms and they are no longer sticky to the touch. Bake for 13 to 14 min., or until they release easily from the pan in one piece. Tops should not brown. Let cool for 2 to 3 min. before transferring to wire rack to finish cooling.
For ganache*: Add ruby chocolate to a medium glass bowl. In a small pot, heat heavy cream until just about to simmer. Pour hot cream over ruby chocolate to cover and let sit 3 to 4 min. Stir until mostly smooth and add butter and Rose Water. Stir until completely smooth. If pieces of unmelted chocolate remain, melt over a hot water bath until smooth. Cool mixture to room temperature. Add ganache to pastry bag.
To assemble: Pipe a generous layer of ganache onto bottoms of half the cookies and top with other half to make sandwiches. Roll sides in crumbled freeze-dried raspberries.