In the bowl of a stand mixer fitted with a paddle attachment, or a handheld mixer, cream together butter, brown sugar, and white sugar for 5 minutes on medium speed until light and fluffy.
Once five minutes is over, add in egg and vanilla and mix until combined.
In a separate bowl, mix flour, baking soda, and salt, and mix until combined. Add these dry ingredients to the butter mixture on low speed, and mix until just combined. Add the chocolate chips or chunks and mix on low until just combined.
Roll out the cookies into big 3 inch sized cookie dough balls, and place on a baking sheet in the freezer for 20 minutes until hard and set. Meanwhile, heat the oven to 350 F (180C).
Place the dough balls close to each other in a deep pan (8x8 or 9x9 inch), nearly touching. Bake 9-12 minutes until golden brown on the edges and soft and gooey in the center.
Sprinkle with flaky sea salt, then scoop out servings using an ice cream scoop while still warm, topping with chocolate sauce, salted caramel, vanilla ice cream, anything you like!
