Place all base ingredients into Thermomix bowl and chop 20 sec/speed 7. Press into 20cm square baking tin that has been lined with baking paper. Place into freezer.
Make the topping by placing dates into Thermomix bowl and chopping 10 sec/speed 7.
Add remaining ingredients except garnish nuts and blend 2 min/speed 9 until smooth and creamy. Pour onto base, sprinkle with chopped nuts and refrigerate until firm.
Cut into slices or squares to serve.