Homemade grapefruit dill cordial

Aris Makris’ recipe, good for 16 oz: place the pulp and zest from two grapefruits and 1.5 oz of dill into a saucepan. Add 8 oz of sugar and muddle, then let the mixture steep for no less than an hour. Pour 16 oz of still mineral water into the saucepan and bring to a boil. Let the resulting liquid cool, then filter into a separate container. Store in the refrigerator.