Boobs, vests and mono-boob

[museumum]

Can anybody suggest a way for big breasted women to wear a vest or other warm underlayer under a shirt or knitwear without creating a mono-boob shelf?
And if the answer is “a cami” I have never found a suitable one so could you post a link? Thank you 🙏

Get a bigger size.

I find I only get a monoboob if the size is too small, so the fabric has to stretch across. In a bigger size there's enough loose fabric to follow the contours of the body