Preheat the oven to 200C/400F degrees.
Grease a muffin tin with butter.
Beat the butter and erythritol together until smooth.
Add the eggs and vanilla. Stir thoroughly.
Add the coconut flour, salt and baking powder. Whisk until there are no lumps and you have a smooth batter.
Pour the mixture into the greased muffin tin and bake for 15 minutes.
Remove the cakes from the tin and allow to cool.
Cut in half, slather with whipped cream and strawberry jam.
Eat and enjoy!