Preheat oven to 180 degrees Celsius (350 degrees Fahrenheit)
Drain away most of the water from soaking the dates, leaving behind a few tablespoons
Use a food processor or blender (or hand-held blender) to blend the dates into a smooth purée (leaving a little water will make it much easier)
Add the puréed dates into a bowl along with all the other ingredients and mix well
Divide the mixture between two greased and lined round baking tins lined with baking paper (I used 18cm/7inch tins)
Bake in oven for around 15 minutes
Once out of the oven, transfer the cakes to a wire rack to cool completely
For the buttercream:
Cook sweet potatoes by boiling, steaming or roasting them until very soft and tender
Discard any skins, and add to a food processor or blender (or hand-held blender) along with all other ingredients
Whizz until completely smooth. Taste and adjust ingredients as necessary - add more maple syrup for sweetness, more salt for saltiness, more cocoa powder for chocolate flavour etc
Leave to cool before using to frost the cake
To frost and decorate the cake:
Place one half of the cake onto a plate and spread just less than half of the buttercream onto it
Place the other half of the cake on top of that and use rest of buttercream to spread on top and around sides of cake
Decorate with rose petals or whatever else you fancy!
Keeps covered in the fridge for up to a few days
Video
Notes
*Several readers have told me they made this cake oil-free by substituting the oil with applesauce, which seems to have worked well. So please do this if you're looking for an oil-free cake! The coconut oil in the buttercream can be omitted, but the taste may not be quite as delicious!