https://variety.com/2019/tv/features/the-simpsons-nancy-cartwright-writing-debut-interview-1203174634/

Cartwright explains what it was like going from longtime voice actor to one of The Simpsons' writers after more than 30 years of voicing Bart. “I like the idea of challenging myself and getting out of my comfort zone,” she tells Variety. “Having been a voice, I’m trying things I’ve never done before as an artist, because I’ve got things to communicate. I’ve found in writing, I can do that. That’s what was the catalyst for writing this particular episode.”

Nancy Cartwright can consider herself lucky. Voice-only actors NEVER get to write or produce for the programs they are featured in. Congratulations to Ms. Cartwright for getting an opportunity like this. I'm sure some of the other FOX-TV animated shows had their voice actors write episodes (for example, Alex Borstein on Family Guy).

Also, have any of the other Simpsons voice cast (like Dan Castellaneta) wrote any previous episodes?