Passionfruit-Mango Macarons

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 100º F.

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.