In the mixing bowl beat the sugar, butter, zest, salt, egg and yolk until combined, 3-4 minutes. Add the flour a little at a time to form a soft dough. Form into a ball or log and wrap in plastic. Chill 60 minutes.
Roll into golf ball size balls, or slice the log into ¼ inch slices or roll the dough to ¼ (or even a bit less) and cut out with medium cookie cutters. Place on 1-2 parchment paper lined baking sheets about 2 inches apart.
Pre-heat oven to 350F/180C.
While the oven is pre-heating chill the cookies, 10-15 minutes. Bake approximately 15-20 minutes or until golden, if slicing or cutting out, bake for approximately 10 minutes then start to check if done. Let cool on the pan 10 minutes then move to a wire rack to cool completely. Enjoy!
Notes
Can I freeze the cookie dough?
Yes. To make this dough ahead, you can store it for up to 3 months in the freezer. You can also make it ahead of time and store up to 3 days in the refrigerator if needed.
How to store cookies?
Store leftover cookies at room temperature in an airtight container for a few days up to a week. You can also store baked and cooled cookies in the freezer in a freezer-safe bag for up to 3 months.