Get the passion fruit juice: Slice the passion fruits in half. Scoop out the seeds and pulp and place it into a bowl. Place a sieve over another bowl, and transfer the seed mixture into the sieve. Use a spoon to press the mixture, scrape it around the sieve to release the juice, for 2-3 minutes. Scrape off any juice sticking to the bottom of the sieve, then discard the seeds (and the purple skin).

Mix the ingredients: Add 2 tsp sugar and a little bit of 1 1/2 cup orange juice to the passion fruit bowl, and stir until all of the sugar is dissolved. Transfer the mixture to a large serving pitcher, and add 2 fl oz Grand Marnier, 2 fl oz tequila, and the remaining orange juice (1 1/2 cup in total). Stir again to incorporate.

Salt the glasses: Add 1/2 tsp lime juice to a flat dish, and 1/4 tsp salt to a second one. Dip your glasses in the lime juice first, then into the salt so it sticks to the rim.

Serve: Add ice to each glass and pour in tequila mixture. Serve right away.