To make the cupcakes:
Preheat oven to 180C. Line 8 muffin cups with cupcake holders.
In a bowl, beat eggs until frothy. Add the sour cream, vanilla extract, water and food colouring to the bowl; combine.
In another bowl, add the almond flour, sweetener, cocoa powder and baking powder. Mix the dry ingredients into the wet ingredients and combine well.
Pour the batter into the cupcake holders, filling 2/3 full. Bake 30 - 35 minutes until done. Insert a toothpick into centre and it should come out clean. Let cool before frosting.
To make the buttercream frosting:
Beat all the ingredients with a mixer until light & fluffy. Spread onto the cupcakes.