Gather the lilac blossoms, choosing those that look healthiest. Remove all green stems or leaves. Give the flowers a good shake or rinse them in cool water to remove any bugs or debris. Let air dry completely.

Add a layer of sugar to the bottom of a clean jar, followed by a layer of dried lilacs. Repeat these layers until the jar is full, with sugar as the last layer. Cover with an airtight lid.

Store the jar in a cool, dark place for up to seven days, shaking the contents to prevent clumping.

After several days of infusing, pour the sugar onto a plate and let it dry out. Once dry, you can choose to remove the lilacs or leave them in the sugar. Store in a dark, cool place.