For the crust grind up the sandwich cookies (with the fillings) in a food processor to fine crumbs. Alternatively you can use any chocolate cookie you like best you will need about 3 cups of crumbs
Add the melted vegan butter & process until it resembles wet sand
Press this mixture into an un-greased pie plate (8") or your un-greased 4" tart molds (6) and refrigerate until needed
Prepare the custard by combining plant milk, sugar, cocoa powder & cornstarch in a medium sauce pot over medium to high heat & bring to a boil stirring constantly to avoid scorching the bottom .
Once it starts to bubble lower the heat but continue stirring & allow it to boil for 20 seconds, cornstarch will only activate when it is brought to a boil so be sure not to take it from the heat too soon!
Remove from the heat & add the vanilla extract, vegan butter & chocolate, stir to melt evenly throughout.
Pour into the prepare pie shell or the tart shells then refrigerate for about 30 minutes to cool & set.
Top with vegan whipped cream & optional chocolate shavings