Preheat oven to 180ºC

In the bowl of a stand mixer fitted with the paddle attachment (or a large bowl with a hand mixer) cream together the butter and sugar until fluffy. (NOTE: if you do not have a mixer you can do this with a wooden spoon. Beat together the butter and sugar until completely combined and fluffy. This will take some time.)

Add the egg and vanilla (if using) to the butter/sugar mixture and mix until incorporated.

Stir in the flour, salt (if using), and the chocolate chips just until combined. Do not mix for a long time after adding the flour, it will create cookies that are too tough or cakey.

Scoop into mounds about 2 TBSP each onto ungreased cookie sheets (you can use a silpat or parchment paper to line your sheets). Do not put more than 9 cookies per sheet

Bake at 180ºC until just set on the edges and middle still looks a little bit undercooked. About 8-12 minutes. (these cookies do not brown as much as other cookies because of the lack of baking soda or baking powder.)

Allow to cool on the baking sheets for 5 minutes before removing. Cookies will continue to cook on the sheets for a few minutes