To make Cake: Place 250g dates into TM bowl and chop 4 sec/speed 7. Remove chopped dates into a pot. Repeat with the other 250g of dates.
Add water and bicarb soda to the pot.
Bring to the boil stirring lightly, and as soon as the mix bubbles take pan off the heat and add the butter. Stir until butter is melted. Set date mix aside and set a timer for 30 minutes. Meanwhile, continue on with the recipe.
Heat oven to 150ºC (fan forced) and place rack into middle. Line 24cm round cake tin with baking paper, and place onto baking tray.
Measure sugar, eggs, flour and vanilla essence into a large bowl and mix together.
Once date mix has cooled for 30 minutes, add to sugar mix and lightly stir through with a large whisk or spatula (do not beat).
Pour mixture into cake tin, even surface with spatula and bake 1 hour and 30 minutes. Test with a skewer, and if necessary add another 10 minutes.
To make Icing: Place sugar, cream, butter and chocolate into TM bowl and cook 4 min/50ºC/speed 2. Add icing sugar and mix 10 sec/speed 3. Stir icing around the top and then mix again 10 sec/speed 3.
Always check your dates for pips before chopping, by bending them in half as you put them into the TM bowl … that way if there is a pip in one, you will pick it up immediately … generally speaking, when using 500g, I have always found at least 1 pip in the dates. If you don't check for pips, the Thermomix will chop them, and you will have hard little pieces throughout the cake … not nice after all your wonderful work.
Icing is best made the day before and left to rest in fridge. Take it out of the fridge the morning you are going to ice the cake to allow it to come to room temperature. You will need to stir it to soften it again before icing the cake. Leftover icing can be frozen.
After icing the cake, decorate it simply with small pieces of chopped dates, or small slices of lightly toasted pecans.