In a medium saucepan, combine one cup of water with one cup of sugar over medium heat. Stir gently until the sugar completely dissolves—avoid boiling the mixture. Once dissolved, remove the syrup from heat and let it cool for about 15 minutes.

Once the syrup has cooled to room temperature, squeeze the juice of fresh lemons to yield approximately one cup. Add this lemon juice to the cooled syrup, stirring well to combine.

Pour the lemon-syrup mixture into a shallow dish, which helps it freeze evenly. Place the dish in the freezer for about 1 hour.

After the first hour, take the dish out of the freezer and use a fork to scrape the frozen edges toward the center. Return the dish to the freezer and repeat this scraping every 30 minutes for about 3 to 4 hours.

Once your granita is light, fluffy, and fully frozen, remove it from the freezer and give it a final scrape to aerate any larger chunks. Serve in small glasses or bowls, garnished with a sprinkle of lemon zest or a fresh mint leaf.