First make the base: Place everything in a food processor or high-power blender and whizz up until thick and smooth. This may take a few goes! Scrape out and into a lined loaf tin. Spread evenly and place in the freezer for at least 30 minutes.
Now make the topping: Place the ingredients in a jug and stir in about 2 tablespoons water or almond milk. Whisk together to create a thick but spreadable sauce - add more liquid to achieve this consistency. Now spread over the base in a thick layer to cover. Return to the freezer for at least 4 hours.
Remove the loaf tin from the freezer 10 minutes beforehand and gently remove the whole thing from the tin, place on a chopping board.
Make the cacao topping: Gently melt the coconut oil and maple syrup, then remove from the heat and whisk in the cacao powder to form a smooth sauce.
Carefully slice into bars (about 8) then drizzle over the chocolate sauce. Sprinkle the cacao nibs over each one - then enjoy!
Keep any spare bars in the freezer for up to 1 month.