Let the basil steep in the warm syrup rather than boiling it—a 15-minute steep pulls out fragrance without bitterness. If freezing without a machine, scrape the sorbet with a fork every 30 to 60 minutes for a light, fluffy, granita-like texture. Swap the lemon and basil for lime and mint for a mojito-style version, or use shaved fennel or zucchini in place of the cucumber. A tiny splash of vodka keeps the sorbet scoopable straight from the freezer. Store in an airtight container in the freezer for up to a week; let it soften a few minutes before scooping.