Line a sheet pan or plate with a piece of parchment paper. Shake a bit of sugar onto a small flat dish.
Dip a fine bristled brush into the egg; shake off any excess. Paint the top and bottom side of a basil leaf with the egg wash—just enough to coat, but not saturate, it.
Dip both sides of the leaf into the sugar. Gently shake to release any excess sugar.
Set the sugar coated basil leaf on the parchment paper. Repeat with as many basil leaves as you like. When done, set the tray in a cool dry place (not the refrigerator or freezer), until they’ve dried completely, 3 to 5 days, depending on the humidity level in your environment.
Once dried, the candied basil leaves will keep in a tin for up to 1 month.