Soak cashews in hot water for at least 2 hours. Cook sweet potato by piercing with a fork and microwaving for 5 minutes, or baking in tin foil for an hour at 375 degrees. Peel and let cool.

Make the crust. Set oven to 350 degrees. Grease the inside of a 9" spring form pan with butter. Add oats and pecans to a food processor and whiz until the texture of sand. Add melted butter, maple syrup and salt and whiz again to combine. Working in batches, evenly press the dough into the spring form pan along the bottom and halfway up the sides. Pierce the bottom of the crust with a fork to allow moisture to escape. Bake for 15-18 minutes until golden and set aside to cool.

Make the filling. Drain and rinse the soaked cashews. In a high-speed blender, combine all filling ingredients and process until super smooth. Pour into cooled spring form pan and put into the freezer for at least 2 hours.

To serve, remove from freezer 15 minutes before serving. Garnish with chopped pecans, flaky sea salt, buckwheat and cacao nibs.