To a large bowl, add the melted butter, brown sugar, white sugar and sesame oil. Mix until combined. Add the eggs, one at a time, until combined. Pour in the vanilla extract and give it a mix.
Add the flour, baking powder, baking soda, salt, sesame seeds and black sesame seeds. Mix the dough just until no flour speckles appear. Add the chocolate chunks or chips and mix once more. Cover the bowl with plastic wrap or a clean kitchen towel and transfer to the fridge to chill for an hour or up to 2 days.
Preheat oven to 350 degrees F. Line two baking sheets with parchment paper.
Using a medium cookie scoop, scoop out balls of dough. If it’s super chilled, you may need to push some dough into the scoop so it’s nice and compact and then release the lever. I like to add all the balls of cookie dough to a sheet of parchment versus scooping dough, as I bake.
Transfer 6 to 7 balls of dough onto the prepared baking sheet, spacing them about 4-inches apart because these do spread. Place in the oven and bake for about 7 to 8 minutes. If the dough is super cold, it may need up to 10 minutes to bake. They should be light to medium golden brown. Sprinkle with a few pinches of salt upon exiting the oven. Repeat until you’ve baked all the cookies.
To freeze, add the cookie dough balls to a baking sheet and stick in the freezer until very cold, about 20 minutes and then transfer to a freezer-safe plastic bag. Bake from frozen at 300 degrees F.