I based this recipe on the banana and chocolate cupcake from The Primrose Bakery Cupcake Book.
125g unsalted butter
250g caster sugar
2 large eggs (free range)
250g plain flour
2tsp baking powder
4 over ripe bananas mashed with a fork
175g plain chocolate chips
Preheat the oven to 160C (fan) and line a 12 hole muffin tin with cupcake cases.
In a large bowl cream together the butter and sugar until light and smooth, about 5 minutes. Add the eggs and vanilla extract and briefly beat again. Add the flour and baking powder and beat until well combined. Stir in the mashed banana and chocolate chips with a wooden spoon..
Carefully spoon the mixture into the cupcake cases, filling them to about two thirds full. Bake in the preheated oven for 20 - 25 minutes.
Remove from the oven and allow to cool in the tin for 10 minutes. Transfer the cakes to a wire rack to cool completely.