Combine water, sugar, and cranberries in a small saucepan over very low heat. Cook, stirring frequently and adjusting heat to maintain a bare simmer, until the cranberries have completely softened, 20 to 25 minutes. Strain mixture through a fine mesh sieve, pressing on cranberries to extract their liquid. Let cool and refrigerate until ready to use. Syrup can be stored in a sealed container in the refrigerator for up to 2 weeks.
