Combine all ingredients, except walnuts, in a flat-bottomed kettle; stir well. Cover and cook over medium heat 20 minutes or until fruit is tender and mixture thickens. Stir frequently to prevent sticking. Blanch walnuts in boiling water 2 minutes; drain well, and chop. Stir into hot fruit mixture.
Quickly pour conserve into hot sterilized jars, leaving 1/4- inch head space. Cover at once with metal lids, and screw bands tight. Process in boiling water bath 15 minutes.