1 1/2-1 2/3cupall purpose flouruse more if needed see post for details
Preheat the oven to 350 degrees F.
In a large bowl cream the melted butter, brown sugar and white sugar for 1-2 minutes. You can use a hand mixer or a stand mixer for this job. Add in the egg and vanilla. Mix just until the egg is combined.
Add in the flour, baking soda and salt. Mix just until combined. The dough should be thick and dry. It should be sticking to your hands. Add in just enough flour to achieve this. If it sticks just slightly to your fingers that is ok, just not making a mess all over your hands when you roll the dough into cookie balls.
Mix in the chocolate chips either by hand or with a few rounds of your mixer. Roll the dough into 2 inch cookie balls. Place at least 2 inches apart on your baking sheet. Bake for 10-12 minutes or until the edges are slightly browned and the centers look underdone. Leave on the baking sheet for 5-10 minutes before removing to cool completely. These cookies will look puffy when they come out of the oven but will settle down as they cool.
Store these cookies in an airtight container for up to 5 days.
Make ahead tip: You can make the cookie dough and chill it in the refrigerator for up to 4 days. Allow to come to room temperature before rolling into balls. Baked cookies freeze well for up to 3 months. Unbaked cookie dough balls freeze well for up to 3 months. Bake frozen cookie dough balls for an extra minute, no need to thaw.