Melt the chocolate and butter: In a microwave-safe bowl or using a double boiler, gently melt the semisweet chocolate and butter together until smooth and glossy. Stir to combine and let cool slightly.

Whisk eggs and sugars: In a large mixing bowl, beat the eggs, granulated sugar, and brown sugar until the mixture is thick and slightly pale. Stir in the vanilla extract.

Combine chocolate with wet ingredients: Pour the melted chocolate mixture into the egg mixture and mix until fully combined and silky.

Add dry ingredients: Whisk together the flour, cocoa powder, baking powder, and salt in a separate bowl. Fold the dry ingredients into the wet mixture until a thick, fudgy batter forms.

Chill the batter: Cover the batter and chill in the refrigerator for 20–30 minutes. Chilling helps the cookies hold their shape and achieve fudgy centers.

Scoop and top: Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper. Scoop rounded tablespoons of batter onto the sheet, spacing them about 2 inches apart. Press a few extra chocolate chips onto the top of each cookie.

Bake the cookies: Bake for 10–12 minutes, or until the tops are shiny and crackly but the centers still feel soft. Avoid overbaking to keep them fudgy.

Cool and serve: Let the cookies cool on the baking sheet for 5–10 minutes before transferring to a wire rack. They will firm up slightly but remain fudgy and chewy inside. Serve warm or at room temperature.