Preheat the oven to 300°F (150°C) and place four 4oz (115 ml) ramekins in a high-sided baking pan. Set aside.
Place a kettle of water over high heat and bring to a boil.
In a medium, heat-proof bowl whisk the sugar, egg yolks and passionfruit pulp together and set aside near the stove.
Pour the heavy cream into a heavy bottomed saucepan and heat until the liquid comes to a simmer.
Whisk the egg yolks constantly while you very gradually drizzle the hot liquid into the eggs. (Do not pour the liquid in all at once or without stirring or the yolks may curdle.)
Strain the mixture into a glass jug with a pour spout and discard any solids left in the strainer.
Divide the custard evenly among the prepared ramekins. If there are any bubbles on the surface of the custard, run your kitchen torch over the tops to pop the bubbles.
Place the pan of filled ramekins on a middle rack in the oven and pour boiling water from the kettle into the baking pan (taking care not to splash any into the custard) until the water comes halfway up the sides of the ramekins.
Bake the custards for 35-45 minutes, until the edges look set but it is still slightly jiggly in the middle. (See video for more detail.)
Remove the custards from the water bath and let cool to room temperature.
Cover and refrigerate the cooled custards for at least 4 hours (and up to 2 days), or until completely chilled.
Right before you are ready to serve, top each custard with a thin, even layer of granulated sugar.
Using a kitchen torch, caramelize the sugar until it is brown. Let cool for a few minutes until the tops are hardened and then serve right away.