Preheat the oven to 180 degrees C. Grease or line some baking trays.
Cream the butter and sugar until smooth. Break the egg in a small bowl and beat well with a fork.
Add the vanilla to the egg. Add the egg mixture to the butter mixture little by little, stirring well with each addition.
Sieve the flour and baking powder into the bowl and stir until smooth. Stir in the cranberries and chocolate chips.
Place heaped teaspoons of the mixture on prepared baking trays, leaving a generous space between each to allow expansion. Flatten with a fork and sprinkle with any remaining chocolate.
Bake in the preheated oven for 10 minutes or until golden brown. Leave to cool for a few minutes before eating.