Heat your immersion circulator to 176 °F/80 °C in a container filled with water.
In a medium bowl add the egg yolks, sugar and salt. Whisk until sugar dissolves, do not blanch the yolks.
In a medium pot on low heat add the cream, lemon verbena leaves, and vanilla extract. Cook with a lid on until the cream boils. Then, allow to rest off heat for 15 minutes, covered as well. Sift the leaves from the cream and set aside.
Add the infused cream to the yolks little by little, whisking just until both mixtures are incorporated.
Slowly pour the mixture into 4-5 wide mouth small mason jars and close them. You must close them gently, so air bubbles are able to escape when the jar is under water.
Put the jars under water and cook for an hour. When finished, the edges should be firm but the center should tremble slightly as the jar moves. Allow to cool completely.
Just before serving, sprinkle the Creme Brulees with white sugar lightly and flambé until you get a deep caramel amber color.