Preheat your oven to 350° F (180° C). Line your cookie sheet with either parchment paper or a silicone baking mat. Set aside.
In the bowl of a stand mixer or with an electric hand mixer, cream together the butter, brown sugar and granulated sugar for 2 minutes.
Add the egg and vanilla, mixing until thoroughly combined.
Add in the flour, baking soda and salt. Mix until your dough comes together.
Lastly, add in the white chocolate chips. Mix until evenly distributed.
Use a cookie scoop to portion out your dough into your desired size. For small cookies, use 1 1/2 tbsp of dough (#50 scoop). For medium cookies use 3 tbsp of dough and for extra large, bakery sized cookies use 1/3 cup of dough.
Arrange on your prepared pan and bake at 350° F (180° C) until the cookies have flattened, spread and are just starting to turn golden brown on the edges. For small cookies, bake 7-9 minutes. For medium cookies, bake 9-11 minutes. for large cookies, bake 11-13 minutes.
Allow the cookies to cool on the pan. Doing this will help finish cooking the insides of the cookie, so it is okay if the cookie looks slightly under-baked when you pull them out of the oven.
Store in an airtight container on the counter for up to 3 days, or in the freezer for up to 3 months.