Sometimes, despite patience and our best efforts, fruit refuses to ripen, and just sits there sullenly in the fruit bowl, obstinately hard as a rock. Is there anything to be done with this unripenable fruit?
First, make sure you've tried putting the fruit in a brown paper bag with a banana, says wyogal. It sounds strange, but ethylene gas (produced by the banana) is what ripens the fruit, she says. Even without the banana, the brown bag keeps the gases in and hastens ripening, says Querencia, so make sure you close the bag tightly. Check the fruit every day, because it can ripen out of control!
If it's still not ripening, though, Spice_zing likes to cut up the fruit and add it to a cup of pineapple or orange juice. "After a few days the hard fruit will absorb the juice and become soft and sweet. Then you can eat it like you would canned fruit, or use in a smoothie," says Spice_zing.
ferventfoodie recommends cooking the stubbornly unripe fruit—perhaps in a crisp or cobbler—with a little extra sugar. pdxgastro recommends pickling, critter101 suggests grilling, and weezieduzzit likes poaching. "Poach it in red wine with some sugar, cardamom pods, and a half of a cinnamon stick, when the fruit is soft take it out and reduce the wine to a syrup," says weezieduzzit. "Serve over good vanilla ice cream."