- 6 cups chopped fresh or frozen rhubarb
- 6 cups sugar
- 2 medium oranges
- Combine rhubarb and sugar in a large heavy saucepan. Grind oranges, including the peels, in a food processor; add to rhubarb mixture. Bring to a boil. Reduce heat and simmer, uncovered, stirring often until marmalade sheets from a spoon, about 1 hour.
- Pour into hot jars, leaving 1/4-in. headspace. Adjust caps. Process in a boiling-water bath for 10 minutes.