01 - Preheat oven to 350°F. Line two large baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
03 - In a large bowl or stand mixer, beat cold cubed butter with light brown sugar and granulated sugar until creamy and slightly fluffy, for 2 to 3 minutes.
04 - Add eggs one at a time, mixing thoroughly after each addition. Stir in vanilla extract.
05 - Gradually add dry ingredients to wet mixture, mixing until just combined. Avoid overmixing the dough.
06 - Fold in semi-sweet chocolate chips or chunks and optional chopped nuts by hand until evenly distributed.
07 - Portion dough into large balls, using approximately 1/4 cup per ball, and arrange spaced apart on prepared baking sheets.
08 - Bake for 14 to 16 minutes, until edges are lightly golden and centers remain slightly underbaked.
09 - Remove baking sheets from oven and let cookies cool on tray for 10 minutes before transferring to a wire rack to finish cooling.