- Preheat the oven to 350ºF.
- Beat together the butter and sugars until smooth. Add the egg and vanilla and mix until smooth.
- Mix together the soda, salt, and flour and add to the wet ingredients. Mix until well incorporated. Add the chocolate and fold it in. Cover with plastic wrap and refrigerate for at least an hour (can prepare up to 48 hours ahead of time).
- After refrigerating, bake on ungreased baking sheets for about 10-12 minutes or until the edges are just becoming golden.