Preheat your oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat.

In a large bowl, beat the unsalted butter, granulated sugar, and light brown sugar until light and fluffy. Mix in the egg and vanilla extract.

Add salt, baking powder, and cocoa powder to the bowl. Then gently mix in the melted chocolate. Gradually add the all-purpose flour, one cup at a time, mixing until the dough comes together. If the dough feels too sticky, chill it in the refrigerator for 15-20 minutes.

Using a small cookie scoop or tablespoon, form dough balls. Roll each ball in granulated sugar and place them 2 inches apart on your prepared baking sheet.