Preheat the oven to 350°F and line 2 baking sheets with parchment paper or spray with non-stick spray.. (To get best results, use parchment paper)
In a medium bowl, whisk or sift the dry ingredients: flour, baking soda and salt together.
In another large bowl, using an electric mixer at medium speed, beat together the butter, and sugars until smooth and mixed together well.
Add the egg and vanilla and mix on low speed until mixed in.
Gradually add the flour mixture and mix in until just incorporated.
Add chocolate chips and continue mixing on low or stir in with a wooden spoon, without overmixing, just until cookie batter is incorporated.
Using a small or large ice cream scoop or heaping tablespoon, drop the cookie dough onto the prepared baking sheets, 6 to 8 per pan, depending on size you are making. To get extra thick cookies, place all the cookie dough scoops in the fridge for 15-30 minutes before baking.
If you like rolling cookie dough balls, you can do that as well, just don't overwork the cookie dough for the best texture and flavor.
Bake the cookies, 1 cookie sheet at a time, until the bottoms and edges are lightly browned and the tops feel firm when lightly touched,
Small cookies bake 8-10 minutes, Large cookies bake 10-13 minutes, Extra large cookies 14-18 minutes
Let the cookies cool for 5 minutes on the baking sheets, then transfer the cookies to wire racks to cool completely.
Makes 15-30 cookies depending on size.