In 2015 I build a MagicMirror in a IKEA TOFTBYN mirror and I just recently refreshed its software. And while documenting it I thought why not share the build here, even if its a bit older, but it runs stable for 5 years now, enjoy.
If you want more details and a step by step installation guide for only MagicMirror on lightweight raspbian lite and only X for display manager, you can find it here:
https://florianmuller.com/build-a-smart-magicmirror-with-two-displays-running-on-raspberry-pi
The mirror also has the option to add 1 to 2 more 24 inch displays in the middle, think I will upgrade soon for more display space :)