Preheat the oven to 300 degrees F. Line cookie sheets with parchment paper, using a 1.5 inch macaron template, trace the circles onto the parchment paper. Or if you have silicon macaron mats, feel free to use them instead.
In a food processor, grind together the freeze-dried raspberries, almond flour, and powdered sugar. Pulse 5-10 times, or until a fine powder is obtained. Sift the dry ingredients through a sieve into a large bowl.
Add half of the egg whites (72 grams) and red food gel into the dry ingredients. Mixed together until well combined. Cover the bowl with plastic wrap and set it aside. (Do not over mix, once everything is incorporated stop.)
In the bowl of an electric mixer, add in the other half of the egg white (72 grams) .
In a small saucepan over medium heat add the caster sugar and water. Using a candy thermometer periodically check the temperature of the sugar syrup. With a reading of 230 degrees F, start whipping the egg whites on medium-high speed using the balloon attachment. When the sugar syrup reaches 240-244 degrees F remove from the heat. Turn down the speed of the electric mixer, and slowly start pouring in the sugar syrup (in a steady stream). Increase the speed of the mixer once all of the sugar syrup is added. Allow the meringue to mix until the bowl is slightly cool to the touch and glossy stiff peaks are formed.
Next it's time to make the macaronage. Add the meringue to the colored mixture (powdered sugar, egg whites, almond flour, raspberry powder) and fold the ingredients together gently using a rubber spatula. Continue to mix until the batter has a glossy shiny appearance. Or until the batter on the rubber spatula flows into a ribbon without breaking with slight movement of your wrist.
To a large pastry bag insert a 1 cm round piping tip, like the Wilton #12. Transfer the batter to the pastry bag.
Pipe the macarons onto the cookie sheet. Pipe straight up about a fourth of an inch away from the cookie sheet. Squeeze the piping bag until the batter covers about three-fourths of the circle. Repeat for all remaining batter. Once completed, tap the cookie sheet on the counter to smooth out the surface of the macaron shells. Basically, lift up the tray about 4-5 inches from the counter-top and drop it, repeat this at least 2-3 times. If any bubbles remain, use a toothpick to remove them.
Leave the macaron shells for 15-30 minutes to dry, or until the shells are no longer sticky to the touch.
Bake the shells for 12-16 minutes. Allow the shells to cool for a few minutes before removing from the baking sheet.
Place the raspberry ganache into a large piping bag. Pipe the raspberry ganache filling into half of the macaron shells. Next, sandwich the macarons together. Transfer the raspberry macarons to an airtight container.
Allow the macarons to mature in the refrigerator for 1-3 days before serving. If in a rush, allow the macarons to chill for 1 hour before serving. After chilling the macarons, allow them to reach room temperature before serving. Enjoy.