In a medium saucepan, melt butter over medium heat until it turns golden brown, about 5-7 minutes.

In a large mixing bowl, combine the browned butter with brown sugar and granulated sugar until smooth.

Add eggs one at a time, mixing well, and then stir in vanilla extract.

In a separate bowl, whisk together flour, baking soda, and salt, then mix into the wet ingredients until just combined.

Fold in toffee bits and optional chocolate chips gently.

Cover and refrigerate dough for at least 30 minutes.

Preheat oven to 350°F (175°C) and prepare baking sheets with parchment.

Drop mounds of dough onto prepared sheets, spacing them 2 inches apart.

Sprinkle flaky sea salt on top before baking.

Bake for 10-12 minutes until edges are golden and centers slightly underbaked.

Let cookies rest for 5 minutes on baking sheet before transferring to a wire rack to cool completely.