Beat for about 2 minutes. Pour in the flour, baking soda, and salt. Blend slowly until properly combined.     Slice the cookie into pieces. Top with vanilla ice cream, if desired. Enjoy!

Summary:
Preheat the oven to 350 degrees Fahrenheit (180 degrees Celsius). Grease a cookie sheet with non-stick cooking spray. Cream the butter, sugar, egg, and vanilla until light and fluffy. Add the peanut butter and stir in the dry ingredients. Fold in the chocolate chips and Reese's Pieces. Flatten and spread the cookie dough on the cookie sheet. Bake the cookie in the oven for about 17-19 minutes. Allow the cookie to cool for about 10 minutes. Serve.