Preheat your oven to 350°F (175°C) and line two cookie sheets with parchment paper.

In a microwave-safe bowl, combine unsalted butter and semi-sweet chocolate, heating in 30-second intervals until melted and smooth. Let cool slightly.

In a large mixing bowl, beat eggs, granulated sugar, and vanilla extract with an electric mixer for 3 to 5 minutes.

Gently mix the cooled chocolate mixture into the egg mixture until fully combined without streaks.

Sift together flour, cocoa powder, salt, and baking soda; fold into wet mixture without over-mixing.

Drop dollops of dough onto the prepared cookie sheets, leaving about 2 inches of space between them.

Bake for 10 minutes until tops are cracked and edges are just set.

Let cool on the pan for 10 minutes before transferring to a wire rack to cool completely.