Melt the butter: Preheat the oven to 375°F (190°C). Line 2 baking sheets with parchment paper and set aside. Place the butter in a large microwave-safe mixing bowl (large enough to make the cookie dough). Microwave for 30 seconds, then whisk. The butter might seem like it has not melted but as you start to stir it and break it up with the whisk it will start to melt. Continue heating in 10-second intervals, whisking after each, until the butter is about three-quarters melted. The butter should be warm but not hot, with a few small solid pieces remaining.
1/2 cup (8 tablespoons; 113 g) unsalted butter
Beat the sugars: Add the brown sugar and granulated sugar to the butter. Whisk vigorously for about 1 minute, until the mixture is smooth, glossy, and slightly pale. (You cannot overmix at this step.)
2/3 cup (133 g) brown sugar, , 1/4 cup (50 g) granulated sugar
Add the wet ingredients, salt, and leaveners: Whisk in the egg, vanilla extract, salt, baking powder, and baking soda until fully combined and smooth.
1 large egg,, 1 teaspoon vanilla extract, 1/2 teaspoon fine salt, 1/2 teaspoon baking powder, 1/4 teaspoon baking soda
Fold in the flour and chocolate chips: Add the flour and fold it in with a spatula until about halfway incorporated. You should still see visible streaks of flour. Add the chocolate chips and continue folding just until no dry flour remains. Do not overmix. The dough will be soft and slightly sticky.
1 1/2 cups (195 g) all-purpose flour, 6 ounces semi-sweet chocolate chips,
Portion the dough: Scoop the dough into about 3-tablespoon portions (12 cookies). Quickly roll each portion between your hands just until smooth, then place on the prepared baking sheet, spacing the dough balls 3 inches apart (6 per baking sheet). Gently press a few additional chocolate chips into the top of each dough ball.
Bake and cool: Bake for 8–10 minutes, or until the edges are set and the centers look slightly underbaked. Let the cookies rest on the baking sheet for 5–10 minutes before transferring to a wire rack to cool completely. If using only one baking sheet, allow the baking sheet to cool fully before baking additional batches for even results.