1) Into a saucepan, put the raisins and add the water.
2) Cook over moderate heat till the raisins are mushy and plump.
3) Strain the mixture and keep the liquid aside for future use.
4) In a food processor, put the raisins and process.
5) Through a sieve, a fine mesh flour strainer or a very dense cheesecloth, strain the raisin pulp.
6) Add the reserved liquid, along with the cayenne.
7) Allow the mixture to cool to room temperature. If a thicker sauce is preferred, blend 2 tablespoons and 1 tablespoon cornstarch together and add it to the final mixture. Gently simmer over low heat till the sauce is thick.
8) Serve or use as preferred (as glaze or finishing sauce).