Prepare the shells (one day ahead):
Separate the egg whites from their yolks and whisk together. Refrigerate in a covered container.
Roast the almond meal at 300ºF for 10 minutes and allow to cool. Mix the
almond meal and confectioner's sugar in a food processor, making sure they don't overheat.
Bake the shells:
The next day, remove the egg whites from the fridge and let them come to room temperature.
Mix together 1 Tbs. of the sugar and the powdered egg white (if using).
In a stand mixer, gently beat half the egg whites with the salt and 2
drops of lemon juice. When the whites begin to foam, incorporate the
sugar-egg white mixture in three additions, raising the mixer speed
after each addition until all the sugar is added. The meringue will
become structured and begin to form soft peaks.If they reach soft peaks
before the syrup is ready (next step), reduce the mixer speed and
continue to run on low speed until you're ready to proceed.
While beating the egg whites, put the remaining 3/4 cup of sugar and 1/4
cup water in a small saucepan. Place over medium heat and stir to
dissolve the sugar. Make sure not to stir once the syrup begins to heat.
When the syrup reaches 230ºF on a candy thermometer, and the egg whites
have reached soft peaks, increase the stand mixer speed to high, and
gently pour the syrup in a steady stream down the side of the mixer
bowl. Turn the speed down to medium and beat this mixture as it cools to
Heat the oven to 300ºF and put 2 baking sheets on racks in the top and bottom thirds of the oven.
While the meringue cools, use a spatula to mix the remaining half of the
egg whites with the sugar-almond meal mixture to achieve what looks
like almond paste, then add yellow food coloring with just a dab of red
to make orange. Slowly incorporate the Italian meringue into this
mixture with a rubber spatula, starting from the middle of the bowl and
moving upward and out. (This is what the French call macaronnage.) The
batter should fall back upon itself in a heavy ribbon.
Transfer the batter to a pastry bag fitted with a 3/8- or 1/4-inch tip.
Pipe the macaron shells in staggered rows onto perforated baking sheets
covered with silicone-lined baking paper or parchment paper. Place the
shells in the oven on the heated baking sheets. Bake for 13 to 15
minutes. Remove the shells from the baking paper (if you're using
regular parchment, you may need to place the paper over a damp surface
to remove the shells easily). Let the shells cool down a bit, turn them
over, and make a small indentation on the flat bottom with your thumb to
make room for the filling.
Make the filling and assemble the macarons:
In a large bowl, mix the sugar and the fruit purées. Whisk in the egg. Put the mixture over a pot of water to create a double boiler and cook until the mixture thickens and reaches 180ºF to 184ºF.
Sprinkle the gelatin over the filling mixture and stir to dissolve.
Cut the butter into small cubes. When the filling has cooled to 104ºF,
add the butter and mix using an immersion blender. Fold in the almond
meal and refrigerate for at least 2 hours.
Transfer the cream to a pastry bag with a tip and use it to fill the macarons by piping a dollop of filling onto one shell and gently topping that with a second shell.
If making ahead, refrigerate the macarons uncovered for a few hours to prevent condensation from forming, then transfer to an airtight container and refrigerate for up to 3 days. Remove them from the refrigerator 15 to 30 minutes before serving.