The night before you want to make this, place two cans of coconut cream into the coldest part of your refrigerator to chill overnight.
To make the crust place the walnuts, dates and cocoa powder into the food processor and process until it starts to clump together into a sticky dough. When you start processing it will initially process into fine crumbs but won't be sticky. The longer you process, the more the nuts will release their oils and then it will start to stick together in clumps.
Press this mixture down into a pie dish and then place into the freezer to set.
Remove the cans of coconut cream from the fridge, being careful not to shake them at all. When you open the can you will see that the cream part has risen to the top. Scoop out only this cream section into a mixing bowl - leaving the water behind. Repeat with the second can.
Add the hardened cream to the bowl of your stand mixer and whip it until it reaches a whipped cream consistency. If the cream won't whip properly and remains quite floppy in consistency, then add in the xanthan gum and whip again.
When the cream is whipped, add the powdered sugar, vanilla extract, peppermint extract and green food coloring and whip again to mix it all in.
Scoop this out on top of the brownie pie crust. Place this into the refrigerator (not freezer) to set.
When you're ready to serve, top with vegan mint chocolate shavings.