Soak cashews and almonds in warm water for one hour. Drain the liquid and pour the nuts into a food processor with dates, coconut oil and process until a sticky crust forms
Press mixture into a lined 9x9inch baking dish and freeze to set the crust
Filling:
Peel the purple sweet potatoes and place into a large pot of water and bring to boil. Cook until tender and then remove from water and cool completely
Blend in the food processor with remaining filling ingredients and combine until smooth
Pour the mixture over the cooled crust and replace in the freezer to firm