@CountryMage:
I am pretty sure that boiling and sweetening are things the MC knows about.
Therefore I come to the conclusion that the herb's effects and the fact that that flower is eatable while being sweet in taste are the actual important points.
That sentence "it's a recipe passed down in my family," does not intent to tell that boiling herbs and sweetening the potion are known in her family but that her family has known about the effects and the taste of that flower for generations.
So it is just a statement that the knowledge about that herb and the flower is not widespread but it is a guaranteed fact that has been passed down in her family.