good egg

基本解释

People said my mother was a good egg. She would always help anyone in need.
人们说我妈妈是a good egg（好人），她总是在别人需要时给予帮助。
You can test eggs by putting them in water, a good egg will sink but a bad egg will rise to the surface.
你可以把鸡蛋放入水中来检验它们的好坏，好蛋会下沉，而坏蛋会浮到水面上来。
dict.cn
A true friend is someone who thinks you are a good egg even though he knows that you are slightly cracked.
真正的朋友是这样一个人：即使知道你稍有裂痕，他也仍然认为你是个“好蛋”。
jialimei1989.blog.163.com

But Mom was a good egg.
NEWYORKER: Tenth of December
If the employer does his due diligence in setting up the plan and the investments options offered are low-cost and well-constructed, then the employee has a good chance of accumulating a nice supplemental nest-egg.
FORBES: How One Florida County Built A Better 457 Retirement Plan For Its Workers
Although there are many egg-warnings on the World Wide Web for computer-literate cooks, there are none on commercial egg cartons: precisely the place where they might do some good.
ECONOMIST: Food safety