Prepare Wet Ingredients: In a large mixing bowl, whisk together melted unsalted butter, pure honey, dark brown sugar, and granulated sugar. Blend for about 2 minutes until light and smooth.

Add Egg and Vanilla: Incorporate one large room-temperature egg and vanilla extract into the mixture. Whisk until fully emulsified, for about another minute.

Combine Dry Ingredients: In a separate bowl, sift together all-purpose flour, baking soda, and kosher salt. Fold these dry ingredients into the wet mixture until just combined.

Chill Dough: Cover the bowl with plastic wrap or a kitchen towel and refrigerate for 30 minutes.

Preheat Oven: While chilling, preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.

Portion Dough: Remove chilled dough, scoop out 2-tablespoon-sized balls and place them on the baking sheet, spaced 3 inches apart.

Bake Cookies: Bake for 10-12 minutes until edges are caramelized and centers appear pale.

Cool and Garnish: Tap the baking sheet to deflate cookies slightly, sprinkle flaky sea salt on top, and let cool for 5 minutes before transferring to a wire rack.