Pour 100ml out of the vodka bottle – you can keep this in the freezer for Christmas cocktails. Mix the rose water and caster sugar together until the sugar dissolves, then pour into the vodka bottle using a funnel.
Wash any sugar off the Turkish delight, then put it in the bottle. Screw on the lid and leave to stand for up to a month, swirling occasionally until the Turkish delight dissolves. Serve with soda water and ice, or drizzle neat over vanilla ice cream for a boozy treat.
Make aheadAfter a month, sieve out any remaining Turkish delight and keep for up to a year. To give as a gift, decant into smaller bottles, adding fresh chunks of Turkish delight.