In a medium sized microwave-safe bowl combine sugar, softened butter, and water. Microwave on high for about 45 seconds or until butter is melted. Stir in 3/4 cup semi-sweet chocolate chips until melted. Stir in egg and vanilla extract, mix well. Add flour and baking soda, stir until combined.
Allow the batter to cool to room temperature (doesn’t take very long).
Then, stir in 3/4 cup milk chocolate chips and remaining 1/4 cup of …