Pre-heat oven to 180°C/160°C fan/gas mark 4. Grease and line two 8 inch round cake tins.
In a medium bowl, whisk together the oat flour, sweet rice flour, tapioca flour and potato flour, baking powder, baking soda, salt, and cinnamon then set aside.
Place the dates and the boiling water in a small food processor or mini blender and blitz until completely smooth, scraping down the sides as and when you need to.
Pour the apple sauce, olive oil, maple syrup, vanilla extract and date paste into a large separate mixing bowl or stand mixer and beat until completely combined.
Add the eggs one at a time, beating well after every addition.
Mix in the dry ingredients, one third at a time to ensure it has all mixed in evenly.
Divide the mixture between the two cake tins and bake in the oven for 30 minutes or until an inserted cocktail stick comes out clean.
Turn out the cakes and cool on wire racks before filling with the jam and covering with buttercream.