add into

add (something) into (something)

To mix or place something into something else. Make sure you add milk into the brownie mix before putting the pan in the oven. Can we add some more herbs into the sauce? It's pretty bland.
See also: add
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

add something into something

 and add
(something) in to introduce something into something else. Now, add the eggs into the mixture. Add in some more eggs.
See also: add
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
In a bowl, dissolve gelatin in 1/2 ounce hot water and add into egg white mixture.