On a sunny day, pour the water into a clear glass bowl.
Clip basil flowers into the bowl. Stir lightly.
Set the bowl by the plant for several hours in the sun, being careful not to touch the water or the plant inside the bowl.
After a few hours, use another stalk of basil flowers, flick the flowers out of the bowl.
Use immediately or preserve the essence for later by adding brandy to the water and storing it in a dark, amber bottle.