Cream together butter and sugars in a stand mixer until smooth, light, and fluffy (about a few minutes).
Scrape the sides of the bowl, then mix in the egg and vanilla until fully combined.
Add flour, baking soda, and salt to the bowl, and mix until just combined.
Stir in chocolate chips until evenly distributed.
Measure dough into 1/4 cup portions for large cookies or 2 tbsp for smaller ones.
Roll dough into a ball, then break it in half and press the two halves back together, leaving jagged edges for texture (optional).
Place dough portions on a baking sheet and bake at 350°F for 13-15 minutes for large cookies, or 9-11 minutes for smaller ones, until edges are golden brown.
Sprinkle with flaky sea salt immediately after baking, and let cool on the pan for 10 minutes before serving warm.