McCormick Culinary Kosher Onion Powder, 20 oz Bottle. McCormick Culinary Onion Powder is a seasoning made from dehydrated ground onions. This product is the perfect fresh onion substitute because it's onion, plain and simple. Use this potent-smelling powder in marinades and dry rubs to add onion flavor without the bulk and moisture of the onion bulb. Onion powder seasoning started as field-grown onions, so you can use it in recipes you'd use fresh onions. Just 1 tablespoon of McCormick onion pow