She is particularly renowned for her famous cookbook titled Hjelpreda i Hushållningen för Unga Fruentimber (Helpful Guide in Housekeeping for Young Women), published in 1755.
An essential reference for homemakers in 18th-century Sweden, this book had several editions and was also translated in German, Danish and Estonian.
In 1710, her mother married the nobleman Eric Rosenstråle, with whom she had seven more children and moved with to Borggård Manor outside Finspång.
The book mostly contains food recipes but also includes instructions on dyeing textiles and other things related to household maintenance.
Warg's work was the leading cookbook for several generations and remained relevant until the late 19th century when new household goods, industrially manufactured kitchen stoves and changes in cuisine made most of its recipes outdated.