01 - In a medium saucepan over medium heat, melt the butter. Continue cooking while swirling occasionally until butter foams and develops a golden brown color and nutty aroma, about 5 to 7 minutes. Remove from heat and allow to cool for 10 minutes.
02 - In a large mixing bowl, whisk together the cooled brown butter, light brown sugar, granulated sugar, and maple syrup until well blended. Add eggs and egg yolk, one at a time, mixing thoroughly after each addition. Incorporate vanilla extract.
03 - In a separate bowl, whisk together all-purpose flour, baking soda, baking powder, and fine sea salt until uniformly mixed.
04 - Gradually add the dry mixture into the wet mixture, stirring gently until just combined. Avoid overmixing.
05 - Gently fold in semisweet chocolate chips and chopped salted pretzels.
06 - Cover the dough and refrigerate for a minimum of 30 minutes or up to 24 hours to enhance flavor and texture.
07 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
08 - Scoop dough into 2-tablespoon portions and arrange on prepared baking sheets, spacing each 2 inches apart.
09 - Bake for 11 to 13 minutes, until the edges are set and centers appear slightly underbaked. Cookies will continue to set as they cool.
10 - Immediately sprinkle with flaky sea salt. Let cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.