The ingredient that substitutes best for onion powder in cooking is chopped fresh onion. The approximate substitution ratio for onion powder to fresh onions is to use 1/4 cup of a chopped fresh onion for every single teaspoon of onion powder. A higher amount of onion can be used as a substitution to create a more potent and intense flavor, while reducing the quantity creates a milder taste.
Onions can be used in the same dishes as onion powder. Substitutions can be made with yellow onions, which have a slightly sweet and mild taste, or red onions, which are tangier and sharper in flavor. As with substituting other ingredients in cooking and baking, using onions to replace onion powder may slightly alter the taste and texture of the end dish. When substituting onion powder with onions, people should note that an onion has a different taste, level of moisture, weight and texture than the powdered form. Onions also have different chemical and physical properties than onion powder, which makes measuring accurately important to achieve a similar finished dish. Some substitutions, such as sweeteners and thickening agents, have differences in levels of acidity as well as potency, which should be taken into consideration when preparing a meal.