• For the milk chocolate and passion fruit ganache: Cut the passion fruits in half, and scoop the seeds into a fine-mesh strainer set over a measuring cup. Using the back of a spoon, press, scrape, and press the seeds again against the strainer to extract as much juice as you can. You should get about 1 tbsp (15 ml) juice per passion fruit.
• In a double boiler or the microwave (at the lowest heat setting), melt the milk chocolate and butter together. Add the passion fruit juice and kosher salt. Mix well, take off the heat and transfer to an airtight container. Reserve until ready to assemble the macarons. Place in the refrigerator if you want the ganache to firm up faster. (The ganache can be made ahead; refrigerate, but make sure to return to room temperature at least an hour before using.)

For the macaron shells:

*Return the egg whites to room temperature at least an hour before making the macarons shells.*

• In the bowl of a food processor, add the powdered sugar and almond flour, and process until the mixture is thoroughly incorporated, 30 seconds to a minute. Sift the mixture through a fine-mesh strainer to make sure no lumps or bigger bits of almonds are left.
• In the bowl of a stand mixer fitted with the whisk attachment, or in a large stainless steel mixing bowl if using a hand mixer, whisk the egg whites on medium/high speed until frothy. Add a tablespoon of the granulated sugar, continue whisking at medium-low speed, then add the remaining sugar slowly. Increase the speed medium-high and whisk until the egg whites are bright white and create stiff peaks. At low speed, mix in three drops of yellow and one drop of orange gel food coloring. The macaron shell mixture should be of a bright warm yellow color. Add more color if required.
• Add the almond and powdered sugar mixture to the egg whites and, using a spatula, gently fold in the dry ingredients: slide your spatula all the way to the bottom of the bowl and come back up to the top. Do this about 6 times to incorporate the dry ingredients, then keep folding for a total of about 14 strokes until no pockets of dry ingredients remain and the mixture drops from the side of the spatula in a slow, lazy ribbon. Start testing the ribbon stage early to avoid overfolding.
• Prepare 2 baking sheets by lining them with parchment paper. Cut out the parchment paper so it fits exactly over the bottom of the sheet to make sure the macarons will lay flat. Slide macaron templates under the parchment paper, if using.
• Transfer the macaron batter to a pastry bag fitted with a 1/2-inch (1.25-cm) round tip. Pipe 1.5-inch (3.8-cm) rounds of batter, evenly spaced but still close to one another as they will not expand much.
• Carefully slide the macaron templates off the baking sheets, if you used them. Using a small fine-mesh strainer, lightly sprinkle dark cocoa powder over the shells. Let the shells rest on the baking sheets for 20 to 30 minutes.
• Preheat the oven to 275°F (135°C) with a rack in the middle position. Bake the macarons for 13 to 16 minutes, rotating the pan after 10 minutes.
• Let the shells cool completely to room temperature before assembling them, about an hour.
• To assemble the macarons: Pair same sized shells together and set side by side on a work surface. Using a small offset spatula, spread some milk chocolate and passion fruit ganache over half of the shells. (If you refrigerated the ganache, let it warm back up to room temperature for at least 30 minutes, or until spreadable.) Close the macarons, gently pressing the second shells over the filling.
• Store the assembled macarons in an airtight container and refrigerate for one night before indulging.

Always bring the macarons back to room temperature before serving.