I looked up the ingredients for the first 'cake mix' that Google showed me.
www.tesco.com/groceries/product/details/?id=275603298
Betty Crocker Red Velvet Cake Mix 450G at £2.25 per packet
Ingredients:
Sugar, Wheat Flour, Palm Fat, Fat Reduced Cocoa Powder (3%), Dextrose, Raising Agents: Monocalcium Phosphate, Sodium Bicarbonate, Whey Powder, Emulsifiers: Propane-1, 2-Dial Esters of Fatty Acids, Mono-Diglycerides of Fatty Acids, Modified Corn Starch, Salt, Stabiliser: Sodium Carboxymethylcellulose, Colours: Paprika Extract, Carmine, Flavouring
To this you need to add the following...
All you need is:
65ml vegetable oil (4 1/2 tbsp)
205ml water
3 medium free range eggs
1 tub of Betty Crocker Vanilla or Cream Cheese Style Icing
2 x 8" well-greased cake tins
So for £2.25 they provide a single serving of flour, sugar, dried milk (in the form of whey powder), baking powder and cocoa powder. You then add oil, water and eggs.
A basic chocolate cake mix from scratch is flour, sugar, fat, eggs, some cocoa powder and vanilla essence if you are feeling generous...
From the
BBC website for a plain sponge
Ingredients
125g/4oz butter or margarine, softened
125g/4oz caster sugar
2 medium eggs
125g/4oz self raising flour
I was always taught to simply switch out 1/2oz of cocoa powder with the self raising flour to make a chocolate sponge cake... This recipe would need doubling to be comparable to packet mix above.