Can a magnificent mansion be created on a demiplane?

Question

Is there any problem with casting spells that create extraplanar spaces (like the mage's magnificent mansion) while on a demiplane?

My wizard wants to create a permanent demiplane (using create demiplane and permanency), but I'm not sure whether just to make the demiplane larger or to have him cast mansion each day he spends there for more space and the goodies that with the mansion.

I found nothing preventing the creation of extradimensional spaces in demiplane, but I want to be sure I'm not missing anything.

Answer 1

There's no problem

The spells create demiplane et al. have no restrictions about making on the created demiplanes openings to other demiplanes, whether such openings are created by a spell like rope trick or mage's magnificent mansion or by a magic item like a bag of holding.

Casting mansion while on the created demiplane makes the mansion entrance really hard to find by anyone trying to hunt you down but also obviously costs a 7th-level spell. I think most folks likely consider the demiplane itself already secure enough, but if you need a place to hide an army or make a refugee camp, and the created demiplane's not big enough on its own, also slapping a mansion entrance on the demiplane is a good plan.