To make lavender sugar, mix 2 tablespoons of spikes of fresh lavender flowers (with the stalks cut off if necessary), or 1 tablespoon of dried lavender flowers, with 1 cup of superfine sugar.
Select a dry glass jar and make alternate layers of sugar and lavender flowers until the jar is full. Cover tightly and leave in a warm room for 1–2 weeks. Give the jar an occasional shake to distribute the scent evenly. Shake the sugar through a nylon sieve before use. Return the lavender flowers to the jar and top up with fresh sugar.