Mary Berry's chocolate chips muffins

I found this lovely recipe in Mary Berry's book "Ultimate cake book". This is one of the best books at my bookshelf.
Last time while I was in Poland I bought silicone flower trays. I think flower-muffins look beautiful.


For 12 muffins we will need:

250 g self-raising flower
1 teaspoon baking powder
50 g soft margarine (I gave butter)
75 g caster sugar
175 g plain chocolate chips
2 extra