Clip fresh lemon verbena stems from the plant. Choose one with several hearty leaves on it. Shake the leaves gently to remove any insects that remain on the plant. Don't wash the leaves, as the added moisture will compromise your extract.
Fill the top pan of a double boiler with 1 cup of good quality olive oil or almond oil. If you don't have a double boiler, use a saucepan inside a skillet that can be filled with water. It's important that whichever you use, water does not get into your oil.
Lightly crush the leaves and stems to release the fragrance of the plant. Put the material into the oil.
Set the burner on a low to medium heat and watch that the water doesn't burn out over the next hour while you steep the oil with the verbena. You must infuse the plant for at least 60 minutes, but you can continue heating the oil for as long as you like, which will strengthen the infusion.
Cool the oil before straining it through a mesh strainer or a piece of cheesecloth, set over a colander.
Pour the herbed oil into a clean, dry glass jar. Canning jars work very well for this project. Cap the jar and store in a cool, dry location. The oil should be used within 6 weeks for maximum freshness.
Place a colander into a stainless steel stock pot and fill with water until it reaches the bottom of the colander. Remove the colander for a moment and add 2-3 cups of fresh lemon verbena stems and leaves to the water. Replace the colander.
Insert a stainless steel or ceramic bowl into the stockpot, placing it on the colander.
Invert the stockpot lid and put it on top of the pot. The lid must have a knob handle in the middle in order to be used for this procedure. Turn the heat on low. You want the herbs to steep, not boil. Keep the heat level low so the herbs are barely simmering.
Fill the inverted lid with ice, two or three trays worth. This will allow condensation to form inside the stockpot.
Simmer the herbs until all the ice has melted. Carefully lift the stockpot lid and discard the ice water into the sink. Inside the stockpot, the bowl in the colander has retained the fragrant water of the lemon verbena. Remove and pour into a glass jar or spray bottle.