Sometimes called powdered onion, granulated onion is made from bulb onions -- as opposed to the green tops -- because that's where the flavor is concentrated. The onions are chopped, dehydrated and ground to a fine powder that adds powerful flavor to foods such as dips and salad dressings that don’t need to be cooked. Granulated onion can also replace chopped onion when cooking, especially when a smooth texture is desired. It's a sneaky way to slip in a little onion flavor when serving finicky eaters, because they won’t be able to see the onion pieces. To substitute, 1 teaspoon of granulated onion replaces 1/3 cup of fresh chopped onion.

Dried chopped onions are the way to go when you want the look and feel of onion without the work of chopping. They are also made with yellow or white bulb onions that have been cut, dried and left in pieces. These dried flakes can be added directly to moist foods, though some brands may require rehydration. Five teaspoons of dehydrated onion soaked in an equal amount of water will yield 1/4 cup of chopped onion. Drain off the excess water or add it to your dish for additional flavor. Some brands also offer toasted dried onion, adding a buttery flavor without the work of sauteéing in oil.

When adding granulated onion powder or dried flakes to foods that won’t be cooked, such as sour-cream based dips, allow several hours for the flavors to open up and meld. Granulated onion will dissolve and incorporate faster than onion flakes, unless you dehydrate the flakes first before adding them. Stirring the dish before serving will also help to distribute the flavor. If you don’t know how much dried dried onion to add to a cooked dish, 1 teaspoon of granulated and 1 tablespoon of dried flakes is the equivalent of one small onion.

To keep your dried onion fresh, avoid pouring the spice directly over a heated dish. Instead, use a measuring spoon or pour into the palm of your hand. Granulated onion readily absorbs moisture and is prone to clumping, especially if no anti-caking agents are added. If your onion powder cakes or sticks to the sides of the container, it can still be used. Refresh it by whirling in the blender or breaking it up with a fork. Dried onion has no expiration date, but as with all spices, it loses its potency over time. To prolong freshness, store away from heat in a cool, dry place.