onion soup mix
A packaged, dehydrated seasoning mix built on onion and beef bouillon flavor, used to make onion soup or stirred into dips, casseroles, and pot roasts as a quick savory shortcut. It's essentially a pre-blended combination of dried onion, salt, bouillon, and a few other seasonings in one packet.
Buying guidance
Brands vary a lot in sodium, sugar, and onion-piece size -- check the label if a dish is sensitive to saltiness, since some packets are salty enough to season it on their own.
Substitutions
- Homemade mix of dried onion flakes, beef bouillon granules, onion powder, garlic powder, and a little pepper -- close in flavor and lets you control the salt.
- Beef bouillon plus sauteed fresh onion -- more work but avoids the packaged mix's saltiness and preservatives.
- A different brand's onion soup mix -- fine 1:1, just taste before adding extra salt.
Tips & common mistakes
The dried onion pieces in the packet need time and moisture to soften -- stirred straight into a cold dip and served right away, they stay crunchy and taste raw, so a cold mixture using the mix benefits from sitting a while before serving.
Storage
An opened packet doesn't keep as well as a jarred single spice would, since the bouillon granules in the mix are more prone to absorbing moisture and clumping into a solid mass -- it's easier to use the whole packet at once than to reseal and store part of one.