Preheat the oven to 350 degrees F (175 degrees C). Line two large baking sheets with parchment paper and spray with nonstick spray.
Combine flour, cocoa powder, baking powder, and 1/2 teaspoon sea salt in a bowl.
Heat butter in a saucepan over low heat until melted, 3 to 5 minutes. Add chocolate chips and stir until completely melted. Remove from the heat.
Beat brown sugar, white sugar, eggs, and vanilla in a bowl with an electric mixer until creamy. Pour in a small amount of chocolate mixture and stir until well combined. Slowly add remaining chocolate mixture, stirring constantly to avoid curdling the eggs. Fold in flour mixture until just combined; do not overmix.
Drop six large scoops of batter about 2 inches apart onto each of the prepared baking sheets.
Bake in the preheated oven until cookies have spread and flattened to a diameter of 4 1/2 inches or larger and the tops are crinkled and puffed, 12 to 14 minutes.
Remove from the oven and place the baking sheets onto a wire rack. Immediately sprinkle the cookies with sea salt. Let cool for 18 to 20 minutes, then use a spatula to transfer cookies to a serving platter.
Salted Chocolate Cookies · Dinner Match Lab | Dinner Match Lab