Sort cranberries, discarding any soft or decayed fruit. Rinse and drain berries. Rinse lemons, trim and discard ends.
Cut lemons into 1-inch chunks and discard seeds.
In a food processor, whirl the cranberries and lemon chunks until they are finely chopped. Or grind the fruit pieces through a food chopper using a fine blade.
Mix fruit and 1 cup sugar (or to taste) in a 2- to 3-quart pan. Bring to a boil over high heat. Reduce heat and simmer, stirring often, until mixture is reduced to about 3 cups, 8 to 10 minutes.
