Preheat the oven to 180C/160C fan or GM5. Line a 20cm square tin with grease proof paper.
Begin by making the sponge. Add the chopped dates to a medium-sized pan and pour over the low-fat coconut milk. Bring to a gentle simmer for about 5 minutes, stirring every so often.
Remove from the heat, and add in the bicarbonate of soda, stirring until completely mixed in. It will fizz up a little,and all those tiny little bubbles are what is going to create the lightness to the sponge. Allow to cool.
Mix together the oil and the sugar, then lightly fold in the self-raising flour. Finally, add the date mixture, and gently fold in so you keep as many of the bubbles as you can. Add in the extra tablespoon of water or any fresh juice if the mixture doesn’t drop off the spoon easily.
Tip into the tin, and bake for 30 minutes, until a skewer comes out clean and the sponge is springy to touch.
To make the sauce, add the coconut milk, dark brown sugar, and treacle to a saucepan, and heat gently. Mix the cornflour with 2 teaspoons of water, and add to the saucepan, stirring constantly until thickened.
Cut the sponge into 12 pieces, and serve with the sauce in a jug for everyone to pour over themselves.
The sponge freezes brilliantly, cut into portions and freeze. The sauce can be cooled, stored in the fridge for up to 2 days and gently reheated once.