As its name would suggest, onion jelly is a savory onion-flavored condiment spread. It is usually transparent brown to opaque brown in appearance, and sometimes has visible pieces of onion or other ingredients suspended in it. There are a number of potential uses for onion jelly, from serving as part of an appetizer to providing a glaze for a main dish. The jelly is made from liquid that has been infused with onions and, in some cases, herbs and seasonings, and then boiled with sugar and pectin until it becomes thick.
Onion jelly shares a thick, sticky, yet spreadable texture with all jellies. Unlike many jellies, however, this variety is savory rather than sweet. Unsurprisingly, it generally tastes strongly of onions, and usually also features secondary flavors which are produced through the use of herbs, sauces, and other flavorings during the jelly-making process. While onion jelly is generally brown in color, some versions are translucent while others are opaque, depending on what they contain and how they were prepared. Sometimes, this type of jelly has fragments of onion, garlic, or other ingredients suspended in it, although again, this can vary depending on the recipe.
Fans of onion jelly often use it as a topping for crackers or toast points, or serve it atop a mild cheese, like brie or goat’s cheese. It can also be combined with cream cheese or sour cream to create a dip for crudités. Some people use the jelly as a glaze, spreading it over a beef roast, lamb chops, or other meat dish prior to cooking. Others use it instead of or in addition to ketchup or mustard when dressing hamburgers or hot dogs.
Many specialty food stores and some supermarkets stock onion jelly, and ambitious cooks can even prepare it at home. To make the jelly, onions which have been chopped and caramelized are simmered with liquids like water, white vinegar, wine, and balsamic vinegar as well as herbs and flavorings such as roasted garlic, rosemary, and salt. Once the liquids have become infused with the essence of the onions and the other solid ingredients, these solids are generally discarded. The remaining liquid is boiled with sugar and pectin, a gelling agent, until it becomes thick and jelly-like. When the jelly is ready, it can be eaten immediately, or poured and sealed into sterile jars and then allowed to age for several weeks or months.