01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper for easy cleanup and to prevent sticking.
02 - Whisk together the flour, baking soda, baking powder, and salt in a medium bowl until well blended. Set aside for later use.
03 - Beat the softened butter, miso paste, brown sugar, and granulated sugar together in a large bowl until creamy and smooth, approximately 2-3 minutes.
04 - Add the eggs one at a time, beating thoroughly after each addition. Mix in the vanilla extract until fully incorporated.
05 - Gradually add the dry ingredients to the wet mixture, mixing just until combined. Be careful not to overmix.
06 - Gently fold in the chocolate chips or chopped chocolate until evenly distributed throughout the dough.
07 - Scoop approximately 2 tablespoons of dough per cookie onto the prepared baking sheets, leaving about 2 inches of space between each cookie.
08 - Sprinkle the tops of the cookies with flaky sea salt if desired for a sweet and salty contrast.
09 - Bake for 11-13 minutes, or until the edges are golden brown while the centers remain slightly soft and underbaked.
10 - Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.