Preheat the oven to 300 degrees F. Line a baking sheet with parchment paper or a silicone baking mat.
Beat the egg whites in the bowl of a stand mixer using the whisk attachment until foamy. Then add the white sugar, cream of tartar and salt. Continue to whip the egg whites until stiff peaks form. Then add the food coloring.
Sift the powdered sugar and almond flour together in a separate medium bowl. This will make a fine powder mixture to create a smooth top. Fold the flour/sugar mixture into the egg white mixture – 65 to 75 good strokes.
Transfer the batter to a piping bag. Pipe out 1-inch rounds on the prepared baking sheet. Tap the pan hard on the counter at least 2 or 3 times to release the air bubbles. This will prevent the tops of your macarons from cracking.
Let them sit out for 20 to 30 minutes (or up to an hour if you want). This will allow them time to dry out a bit before hitting the hot oven. They should be "tacky" to the touch but not stick to your fingertips. This is another important step to assure your macarons develop feet! When they dry out they can't spread out in the oven and are forced to rise up.
Bake for 20 minutes. DO NOT UNDER BAKE, even if they look done! Otherwise they will stick to your tray.
Remove from the oven and let cool for 5 to 10 minutes on the pan before trying to remove.
Either make the fillings at this time or store in an air-tight container until ready to use.
Spread a little of the ganache or caramel on half the cookies. Sandwich the other half on top.
Place the chocolate in a heatproof bowl.
Bring the cream to a bare simmer in a medium saucepan over low heat.
Pour the hot cream over the chocolate and stir until smooth. Add the bourbon stir to combine. Allow to cool until thickened slightly (the room temperature ganache should be about the consistency of peanut butter). If it's too thick, you can add a little bit more hot cream and stir until smooth.
Passion Fruit Caramel:
Line a baking sheet with a silicone baking mat.
Scrape the beans from the vanilla bean pod and add to a saucepan with the cream, butter and salt. Heat on medium to melt the butter. Turn off the heat and let the vanilla bean seeds steep for 10 minutes.
In a separate saucepan, boil the passion fruit pulp until it is reduced by half, stirring occasionally, about 10 minutes. Once the passion fruit is reduced, remove it from the heat and stir in the sugars and vanilla/cream mixture. Put the pan back on medium heat and cook until a candy thermometer reads 252 degrees F.
Remove the caramel from the heat and pour onto the prepared baking sheet. Let cool to warm room temperature before using.