1In a sauce pan, melt butter. Add sugars and mix until dissolved. Pour into mixing bowl, cover, refrigerate 10 to 20 minutes.
2In another bowl, mix flour, oats, soda, salt, cinnamon. Set aside.
3Remove bowl from refrigerator. Add egg, egg yolk & vanilla to sugar mixture. Mix well.
4Add flour mixture to wet ingredients. Mix until incorporated. Add chips. Cover and return to refrigerator for about 30 minutes.
5Prepare pan by lining with parchment paper. Preheat oven to 325 degrees.
6Roll dough into balls about walnut size. Place about 2 inches part on pans. Bake 12 to 15 minutes, or until golden brown. Remove from oven, place on wore rack for about 5 minutes. Remove cookies from pan and finish cooling on wire rack.