Dufflet Rosenberg's Chocolate Shortbread Cookies, a recipe on the Worldwide Gourmet

Ingredients

• - 125 ml (1/2 cup) butter, at room temperature
• - 125 ml (1/2 cup) icing sugar
• - 2 ml (1/2 tsp.) pure vanilla extract
• - 5 ml (1 tsp.) water
• - 180 ml (3/4 cup) all-purpose flour
• - 45 ml (3 tbsp.) cocoa powder
• - 15 ml (1 tbsp.) unsalted butter
• - A pinch of salt
• - 75 ml (1/3 cup) semisweet mini chocolate chips