Preheat the oven to 180C/350F degrees
Grease and line a rectangle baking tin with parchment paper.
Beat the egg whites until stiff peaks form.
In another bowl, beat the egg yolks and erythritol together.
Add the peanut flour, baking powder and salt.
Gently fold in the egg whites and combine thoroughly.
Pour into the baking tin and smooth evenly.
Bake for 15 minutes until firm and golden.
Remove from the oven and place on another piece of parchment paper.
Using the parchment paper on the top (will be the one used for baking), gently roll up the cake. Watch your hands and don’t burn yourself! Best to let it cool slightly before rolling. This is to keep the sponge in the correct shape before adding the filling.
Allow to cool.
Make the filling by simply blending all the ingredients together.
Gently unroll the cake, remove the top layer of parchment paper and spread the filling evenly over the sponge.
Using the outer layer of parchment paper roll up the sponge again.
Slice, eat and enjoy!