*If you use unsalted butter then add 1/4 teaspoon of salt.
In a medium bowl, cream until light peanut butter, butter and sugar, add egg and mix well.
In a medium bowl whisk together flour, salt and baking soda then add chocolate chips.
Add whisked ingredients to the creamed mixture and mix well with a wooden spoon.
Shape into a log, approximately 8 x 2 1/2 inches (20 x 6 cm) and wrap with plastic, refrigerate at least 1 hour or even over-night.
Pre-heat oven to 350° (180° celsius). Line 2 cookie sheets with parchment paper.
Remove the log from fridge, and cut 1/4 inch slices with a sharp knife (the knife may push down on the dough, so just reshape into circles). Place on prepared cookie sheets, flatten with a fork (dip fork lightly in flour so the dough doesn't stick), place in the fridge for 15 minutes then bake for approximately 10-12 minutes. Let cool completely before eating. Enjoy!