Preheat your oven to 355°F (180°C). Line a cookie sheet with parchment paper.

Melt the butter in a saucepan over medium heat, stirring frequently until it develops golden brown bits and a nutty aroma. Remove from heat and cool in a heat-safe container.

Let the browned butter cool to room temperature.

In a large mixing bowl, combine the brown sugar, granulated sugar, and cooled brown butter. Whisk until thick and creamy.

Add the egg, sea salt, and vanilla extract to the mixture. Whisk thoroughly.

Sift in the flour, cocoa powder, and baking soda. Stir until a thick dough forms.

Stir in most of the chopped dark chocolate, reserving about ¼ cup for topping. Gently fold in the raspberries.

Scoop the dough into balls and place on the baking sheet, spaced out.

Press the reserved chopped chocolate on top of each cookie dough ball. Sprinkle with flaky salt.

Bake for 8-10 minutes, checking for fudgier cookies at 8 minutes.

Allow the cookies to cool on the sheet before transferring to a wire rack.