Line a 12 cup cake pan with 12 cup cake papers
Place butter, sugar, eggs, flour and vanilla in the mixer. Beat 3 minutes until mixture is light and creamy. Divide mixture and pour in cup cake pan evenly. Sprinkle chocolate chips on top of each cup cake and mix carefully. Bake in preheated moderate oven to 350ºF (180ºC) for 20 minutes or until cupcakes rise and are firm to touch.
Remove from the oven and cool for 10 minutes. Transfer cupcakes to a wire rack and cool completely.
Sift confectioners sugar over the cupcakes.