• 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 starch, 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.

Blueberry Chia Jam

• Place all the ingredients, except for the chia seeds in a small saucepan and cook on a low heat for 5-10 minutes until the blueberries have broken down.
• Blend the blueberry mixture a little bit, you don’t want it too smooth but a little bit pulpy.
• Pour the blueberries into a small bowl and stir in the chia seeds until combined. Place in the fridge for an hour to set.

Maple Swiss Meringue Buttercream

• Heat the egg whites and maple syrup in a bain marie, stirring constantly until the temperature has reached 71°C.
• Remove from the heat and pour into a stand mixer with a whisk attachment. Whisk until the mixture forms stiff peaks and the temperature has reduced to about 32°C.
• Change the attachment to a paddle attachment. On a low speed add the butter slowly cube by cube. When you have almost added all the butter the mixture will look curdled. Do not fret – this is supposed to happen and just means you are nearly done, just continue to add all the butter. Once the butter is totally incorporated the buttercream will miraculously become a smooth velvety consistency.
• Add the salt, and vanilla extract and mix until thoroughly combined.

Assembly

• The sponges often come out of the oven slightly domed and so to make the cake assembly easier I often trim the very top of the dome off each layer so they have a flatter surface to work on. Don’t trim too much or you will lose a lot of cake.
• Place one of the sponge layers on an 8 inch cake board and pipe a circle of buttercream at the very edge of the surface of the cake to act like a dam for the blueberry jam.
• Spread three-quarters of the blueberry jam on top of the sponge, right to the edges of the buttercream dam.
• Place the second sponge layer on top and cover the top and the sides of the cake with the buttercream.
• Reserve a little of the buttercream to mix with the leftover blueberry jam to pipe around the top of the cake for decoration.*
• Decorate with extra blueberries.