In a food processor or coffee grinder, grind the lavender buds to a fine powder. Transfer to a small bowl.

Add the water. With a fork, mix until a clumpy, sandy mixture forms. If necessary, add a bit more water. The sugar should clump together when squeezed.

With your fingertips, very firmly pack the damp sugar mixture into the silicone mold.

Scrape away the excess with a bench scraper, then press the sugar down again using the scrapings to fill any holes or gaps.

Sit the mold on a small tray. Set aside to dry, uncovered, overnight or until sugar cubes are dry to the touch.

Invert the mold onto the tray, and carefully pop the sugar cubes from the mold.

Store lavender sugar cubes in a glass jar or airtight container at room temperature for up to 1 year.