01 - Place butter in a saucepan over medium heat. Melt and cook, stirring frequently, until it foams and golden-brown bits form at the bottom of the pan, approximately 4 to 5 minutes. Remove from heat and let cool for 10 minutes.
02 - In a medium bowl, whisk together the all-purpose flour, baking soda, and fine sea salt. Set aside.
03 - In a large bowl, combine the browned butter, packed light brown sugar, and granulated sugar. Beat until fully incorporated. Add eggs one at a time, mixing well after each addition, then blend in the vanilla extract until smooth.
04 - Gradually add the dry ingredient mixture to the wet mixture, mixing just until incorporated. Do not overmix.
05 - Gently fold in the semisweet chocolate chips, toffee bits, chopped caramel pieces, and roughly chopped pretzels until evenly distributed throughout the dough.
06 - Cover the dough tightly and refrigerate for at least 30 minutes. For thicker cookies, chill up to overnight.
07 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
08 - Using a cookie scoop or tablespoon, portion 2-tablespoon mounds of dough onto the prepared baking sheets, spacing them approximately 2 inches apart.
09 - Bake for 10 to 12 minutes, or until the edges are golden and the centers are just barely set.
10 - Remove from oven and immediately sprinkle the tops with flaky sea salt. Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.