The slow-cooker method, which is included here, produces a mound of unctuous and brown onions. Their fragrance fills the house long after they have turned jammy.
But I think their taste and texture are compromised by the fact that they are essentially - and lovelessly - steaming in a closed pot. They have a faux air about them - but let's agree that it's perfectly OK to work with the time and energy available.
In any case, especially in the winter, a pot of caramelized onions in the fridge can be your best buddy, a go-to ingredient that answers the "what-will-I make" question when the mind otherwise goes blank.
Caramelization, a chemical process that can be used with all vegetables and other foodstuffs, takes place when water - onions are largely composed of water - is cooked out and the vegetable's sugars are concentrated and then browned, almost to the shade of maple syrup. In the process, the raw and biting flavor of the onions (yellow onions are best for this) becomes rounder and sweet.
Caramelized onions can be mixed into pasta dishes, splashed with Pernod, or mixed with cheese and placed on toasted bread slices as appetizers, used in omelets and on sandwiches. Combined with sour cream and the like, they are the backbone of many styles of dip. Pizza crust is another perfect platform.
In his acclaimed book How to Cook Everything Vegetarian, New York Times food writer and cookbook author Mark Bittman writes that caramelized onions can dissolve into and flavorfully thicken soups and sauces - the pork and cider recipe here involves just that - and perform admirably as a garnish. They can also be a lovely addition to quiche and bread doughs and can be a side dish in themselves.
