Pour the boiling water over the dates, stir in the bicarb and leave to sit for 15 minutes.
Preheat oven to 180 degrees.
Add the dates and their water and all other ingredients to a food processor. Process for 3 minutes, or until smooth.
Pour into a square silicone baking dish or grease and line and traditional one.
Bake at 180 degrees for 45 minutes.
Remove from the pan and cool for 10 minutes on a rack before putting on a plate.
Syrup
Combine the sugar and water in a saucepan and bring to the boil.
Drop back to a simmer (about half heat) and simmer until thick and sticky. Stir in the coconut milk and vanilla and bring to the boil again, then simmer for 10-15 minutes.