I have made cakes using paleo muffin mix with the same technique as muffins, but to me it felt a little flat. SO I added an extra egg, separated the two eggs, whipped the whites, and result! A lighter, fluffier cake without needing to add any baking powder. Although check this out if you want to make your own paleo baking powder.
Preheat oven to 180 and grease or line your cake tin (medium)
Separate the two eggs
Add the yolks to the water and oil and mix
Add the muffin mix to the wet ingredients and mix
Whip the egg whites till they are stiff peaks
Mix 1/4 of egg whites into the batter, then gently fold in the rest until no whites are visible.
Pour into your greased or lined cake tin
Add as many raspberries as you like (I like lots)
Bake for around 25 min depending on your oven (start checking at 20 min)
Enjoy with a cup of tea, a good book or a good friend.