• Begin by preheating the oven to 325°F (163°C) and preparing a water bath. Whisk the egg yolks with 1/2 cup (100 g) of the sugar until you achieve a smooth consistency.

For the Custard:

• In a saucepan, gently warm the heavy cream with the espresso powder and salt over medium heat. Once it begins to simmer, remove it from heat and add the vanilla extract.
• Gradually mix about half a cup of this warm cream into the egg yolk mixture while constantly whisking to prevent scrambling. Then, incorporate this egg mixture back into the remaining cream, whisking thoroughly.
• Arrange the ramekins in a large baking dish and fill each one with the custard, leveling off at the brim. Carefully pour hot water into the dish, reaching halfway up the sides of the ramekins.
• Bake for approximately 35 minutes, but check at 30 minutes. The edges should be firm with a slight jiggle in the center, ideally achieving an internal temperature of 170°F (77°C).
• Remove the ramekins from the hot water bath and let them cool on a wire rack for at least an hour. Afterward, loosely cover them and refrigerate for a minimum of 4 hours or up to 2 days.

For Caramelizing:

• Right before serving, evenly sprinkle the remaining sugar atop each custard. Using a kitchen torch, caramelize the sugar until it turns golden and crisp on the surface. Enjoy immediately for that perfect crackling top, or keep it chilled for up to an hour before serving.