Prickly Pear Marmalade

3 C. chopped and seeded oranges (about 2 lg.)
1 C. thinly sliced lemon (about 2 med.)
1 qt. water
1 qt. chopped, peeled, seeded prickly pears (about 9 med.)
6 C. sugar

Combine oranges, lemon and water in a large suacepot; simmer 5 mins. Cover and let stand 12-18 hrs in a cool place. Cook rapidly until peel is tender, about 30 mins. Stir in prickly pears. Add sugar; bring slowly to a boil, stirring until
sugar dissolves. Cook rapidly to gelling point. As mixture thickens, stir frequently to prevent sticking. Remove from heat. Skim foam if necessary. Ladle hot marmalade into hot jars, leaving 1/4" headspace. Adjust two-piece caps.
Process 15 mins. in a boiling-water canner. Yield: about 6 half-pints.