Preheat oven to 350°FStir the graham cracker crust ingredients together. Pour into a 9 inch pie/tart pan and pack in very tightly. Bake for 13-15 minutes or until very lightly browned around the edges. Remove from the oven and allow to cool for 15 minutes before adding the filling.. Using a hand mixer or a stand mixer fitted with paddle attachment, beat the softened cannabutter on medium-high speed until completely smooth and creamy, about 2 minutes. Add the confectioners’ sugar, vanilla extract, and salt and beat until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl as needed. Add the peanut butter and beat until smooth and combined.
Spread filling evenly into tart crust. Set aside as you prepare the topping.
Using the microwave, melt the chocolate and peanut butter together until smooth. If using the microwave, stop and stir every 15 seconds until melted. Pour and spread over filling.
Chill in the refrigerator, uncovered, for 4-6 hours (or up to 2 days) before slicing. If chilling for longer than 6 hours, cover it.