Preheat oven to 175C/350F. Take an 8 inch (20cm) Square cake tin and line it with baking paper. Make sure the paper is long on 2 of the sides to help remove the cake once the sauce has been added.
Place the egg whites into the clean bowl of a kitchen stand mixer fitted with a whisk attachment.
Whisk the egg whites on medium/high until soft peaks form.
Slowly add the maple syrup, 1 tablespoon at a time, until large peaks have formed,
Continue whisking on medium/high and add the vanilla extract.
Add the egg yolks, one at a time. Only add the next yolk when the previous one has been fully incorporated. Whilst still whisking, add the milk and vinegar into the egg mixture.
In a separate bowl, lightly whisk the coconut flour and baking powder together. Ensure that the coconut flour has no lumps in it.
Turn the whisk to low and add the flour mixture. (If you keep it on high then you will most likely end up wearing the flour). Once incorporated, return the whisk speed to medium/high to fully mix all the ingredients.
Pour the batter into the tin and smooth out the top. Bake for 30 minutes or until a toothpick inserted in the centre comes out clean.
Allow the cake to cool in the tin for 30 minutes.
After 30 minutes take the end of a wooden spoon and 'poke' holes in the cake at regular intervals (I did 4 or 5 rows of 5 holes; so 16-20 'pokes'). Do not make the holes too close together and do not push too far down; about 1/2 way is right.
Reserve 1/2 Cup of Raspberry sauce (this is for the Raspberry Cream which should already be made) and pour the rest over the Cake and spread it over the top and into the holes. Allow the cake to sit for at least 30 minutes in the fridge.
Remove the cake from the tin using the longer edges of baking paper and place on a serving tray.
Pipe the Raspberry Cream in lines over the top of the cake. Top with coconut.
Serve and devour!
The cake needs to be kept in the fridge.