Make the ganache: place chopped dark chocolate in a bowl. Heat cream until simmering, pour over chocolate, let sit 1 minute, then whisk until smooth. Chill 30 minutes, then scoop 12 mounds onto a parchment-lined plate and freeze until solid, about 15 minutes.

Beat the melted butter with both sugars until thick and lighter, about 2 minutes. Add egg and vanilla, beat until smooth.

Whisk flour, baking soda, and salt, then fold into the wet mix. Stir in chocolate chips until just combined.

Scoop 12 dough balls, flatten each, place a frozen ganache disc in the center, and wrap the dough around to seal. Roll into balls and chill if needed.

Preheat oven to 350°F (175°C). Arrange on parchment-lined sheets and bake 12 to 14 minutes until edges are golden and centers look soft. Cool 5 minutes on the sheet, then transfer to a rack.