1) Ingredients: 1 cup (240 ml) freshly squeezed lime juice (about 8–10 limes), 1 cup (240 ml) simple syrup (1:1 sugar to water). 2) Make simple syrup: In a small saucepan combine 1 cup sugar and 1 cup water. Warm gently, stirring, until the sugar is fully dissolved. Do not boil. Remove from heat and cool to room temperature. 3) Juice limes: Roll limes to soften, cut in half, and juice. Strain juice through a fine mesh strainer into a measuring cup to remove pulp and seeds. 4) Combine: Stir or whisk 1 cup strained lime juice with 1 cup cooled simple syrup until homogeneous. Taste and adjust: add up to 2 tablespoons extra syrup if you prefer sweeter, or dilute with a tablespoon of water if too sweet. 5) Bottle: Transfer the mix to a clean airtight bottle or jar. Label with date. 6) Use: Shake or stir before each use (separation can occur). Use in cocktails in place of commercial sour mix at a 1:1 substitution for lime-based recipes. Optional variations: use rich syrup (2:1 sugar:water) for a silkier mouthfeel—reduce syrup volume to taste.