Get the oven up to 190C. You'll need 24 of those wee cup cake papers. If these are for kids then get multicoloured ones.

Cream the butter and sugar really well until it's frothy like a head of beer. Add your eggs one at a time and beat well after each one goes in. Then sift in your flour and baking powder and throw in the milk. Mix the flour etc through with a wooden spoon - don't beat or overmix. 

Put a large teaspoonful of mixture into each paper case. Bake for about 15 - 20 mins. 

Tip: These will impress the kids even more if you have different coloured icing. Just make the plain vanilla icing, separate it into three different lots and add a couple of drops of food colouring to each lot before swirling it on to the top of the cup cakes.