Anna Margrethe Lasson was born in Copenhagen and grew up in Dalum Monastery on Funen, where her father was a High Court judge. After her father's death in 1706, she went to live with a married sister. The sisters subsequently moved to a priory in Odense, where they lived in impecunious circumstances, weighed down by the debts left by their deceased father. In 1730 the estate was put up for auction; however, the two sisters were allowed to remain there for the rest of their lives.
Anna Margrethe Lasson wrote a poem as homage to the Norwegian hymn writer Dorothe Engelsbretdatter’s work Taareoffer, in which she defends the ability of women to write. She wrote the first original Nordic prose novel Den beklædte Sandhed, published in 1723 under the pseudonym "Det danske Sprogs inderlige Elskerinde Aminda". It is a novel about modest love, modelled on French and German works and adapted as a roman à clef about the marriage of the Danish Prince George and the English Princess Anne of Great Britain.