Melt chocolate and butter:

In a heatproof bowl set over a saucepan of simmering water (or microwave in 30-second intervals), melt the butter and unsweetened chocolate together, stirring until smooth. Remove from heat.

Combine with sugar:

Whisk in the granulated sugar until fully incorporated.

Add eggs and vanilla:

Whisk in the eggs one at a time, followed by the vanilla extract.

Prepare dry ingredients:

In a separate bowl, whisk together the flour, cocoa powder, and salt.

Combine wet and dry ingredients:

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.

Stir in chocolate chips:

Gently fold in the chocolate chips.

Chill (optional but recommended):

Cover the dough and chill for at least 30 minutes (or up to overnight) for a chewier texture.

Preheat and prepare:

Preheat oven to 350°F (175°C).

Line a baking sheet with parchment paper.

Scoop and bake:

Drop rounded tablespoons of cookie dough onto the prepared baking sheet, spacing them apart.

Sprinkle with salt:

Lightly sprinkle the tops with flaky sea salt.

Bake:

Bake for 10-12 minutes, or until the edges are set but the centers remain slightly soft.

Cool and serve:

Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack.