1) Sanitize: Sterilize a bottle or jar by boiling it in water for 5 minutes or running it through a dishwasher on high heat. Let it dry. 2) Zest and juice: Zest 6–8 limes (about 2 tbsp / 12–15 g zest) and then juice enough limes to yield 2 cups (480 mL) fresh lime juice. Strain juice to remove seeds and excess pulp if desired. 3) Make syrup: In a small saucepan combine 1 cup (200 g) granulated sugar and 1 cup (240 mL) water. Heat gently, stirring, until the sugar is fully dissolved. Bring to a very gentle simmer for 1–2 minutes (do not vigorously boil). 4) Infuse zest: Add the lime zest to the hot syrup, remove from heat, and let steep for 10–15 minutes to extract aromatic oils. 5) Combine and adjust: Strain out the zest and return the syrup to a clean container. Stir in the 2 cups (480 mL) fresh lime juice. Taste and, if desired, add up to 1–2 tbsp additional sugar (or simple syrup) to reach your preferred sweetness. Optional: dissolve 1/2 tsp citric acid (for tartness/preservation) and a pinch of salt to round flavors. 6) Cool and bottle: Allow the cordial to cool to room temperature, transfer to the sterilized bottle or jar, seal tightly, and refrigerate. 7) Use: Shake before using. Typical cocktail usage is 15–30 mL (1/2–1 fl oz) per drink depending on recipe and taste. For longer storage, freeze in ice cube trays and thaw as needed.