Combine the mango slices and water in a saucepan and boil over moderate heat for 15 minutes, until the mangoes are tender.
Press this mixture through a sieve, or process in an electric blender or food processor until smooth. Return to the saucepan and add the sugar and vanilla extrac Tbsp Boil for 30 to 40 minutes, until thick and the proper consistency for a jam. Pour into hot sterilized jars and seal.
Servings: 2 quarts