Depending on how it is used in food, onion may be considered a vegetable or a spice. As a spice, onions flavor more dishes around the world than any other spice. The flavour they offer depends on preparation details and can include a whole gamut of aroma and pungency from mild and bitter to sweet and mellow. Also consider all the different varieties of onions regarding shapes, colours, and sizes, and things get even more interesting.
From the health perspective, onions have appeared in the pharmacopeias of many traditional medical systems with uses ranging from antiseptics and treatments for colds and flu to treating allergies and scars. Closely related to garlic, they too have many important phytochemicals (e.g. quercetin and allicin) that assist in the prevention of several chronic diseases including some cancers, cardiovascular disease, diabetes and even osteoporosis.
Let’s get back to how to use onions for flavour. I have decided to include a recipe for caramelized onions as they offer incredible depth to a variety of dishes. Here are some examples:
Since onions have a high concentration of water and sugar, the key to caramelizing them is to see that this released at a slow and steady rate. There are several ways to do this, and you will find recipes with all sorts of ingredients (like balsamic vinegar, salt, stock, sugar etc.). I am all for fewer ingredients and keeping things simple and allowing the food to offer its inherent flavours.
Warning: this recipe requires patience as it takes about 30min for the onions sugar to caramelize. If heat is too high, they will burn.
2 onions – sliced about 0.3 cm (sliced too thinly they burn) (about 2 cups)
30 cm pan (does not have to be non-stick)
1 tbsp olive oil or 1 tbsp butter/mixed with oil
1-2 tbsp water
Note that the spice “onion seeds” is also known as Nigella seeds but is from a different plant and is unrelated to onion.