Preheat the oven to 320°F (160°C).
Pour the heavy cream into a high-sided stockpot (heavy cream rises fast when boiled); add lemongrass pieces and bring it to a boil. Turn off heat and let sit for 20 minutes to allow for lemongrass flavour to “infuse” into the heavy cream.
In a separate bowl, whisk the sugar and egg yolks.
Bring the heavy cream back to a boil, turn heat to low. Temper the sugar/egg yolks by adding 1/3 hot, heavy cream at a time very slowly into the sugar/egg mixture and whisk. When all the heavy cream has been added to the sugar/egg yolk mixture, return to the pot and whisk on very low heat for just a minute.***
Strain through a fine-mesh strainer to remove minor egg pieces and lemongrass. Place your ramekins into a “hotel pan” or pan with sides at least 4 inches high to accommodate water around the ramekins.
Place the pan on a sheet pan and into the oven; carefully pour the mixture with a vessel with a spout such as a Pyrex measuring cup into ramekins close to the top of each. Pour water into the pan to the halfway mark around each ramekin.****
Bake for approximately 30 minutes, or until crème brûlée has “set” like custard and does not move when jiggled; do not overcook.
Cool, refrigerate overnight and use the next day.
To finish, sprinkle granulated sugar on top lightly and burn with a propane torch that can be purchased at your local hardware store.