You're supposed to eat the spinach.
3 seconds sound clip from the Matilda (1996) movie soundboard.
You can hear this line at 00:02:37.930 in the Blu-ray version of the movie.
Quote context
[...]
- Get out of the street, you little dodos!
- Had they paid any attention to her at all they'd have realized she was a rather extraordinary child.
- Oh, my gosh, Matilda, now look what you did!
- You're supposed to eat the spinach.
- Babies! You're better off raising tomatoes.
- As time went by, she developed a sense of style.
- Every morning, Matilda's older brother, Michael, went to school. Come on, get out of here.
[...]