Bit more info, this is a common combination for stocks, soups and stews in French cuisine, traditionally 2:1:1 ratio onions to carrots and celery.
In Italian cuisine the essentially same thing is Sofrito, there is also the Cajun Holy Trinity which varies ingredients but is for similar purposes.
This is kind of a staple for a lot of quality cooking, you should at least make a stock from scratch at some point in your life and you’ll see why these combinations are so important if you do so.
Bit more info, this is a common combination for stocks, soups and stews in French cuisine, traditionally 2:1:1 ratio onions to carrots and celery.
In Italian cuisine the essentially same thing is Sofrito, there is also the Cajun Holy Trinity which varies ingredients but is for similar purposes.
This is kind of a staple for a lot of quality cooking, you should at least make a stock from scratch at some point in your life and you’ll see why these combinations are so important if you do so.