01 -
Preheat oven to 350 °F and spray a 9-inch springform pan or equivalent with nonstick cooking spray.
02 -
Using an electric mixer, beat the butter and brown sugar until light and fluffy, approximately 4 minutes.
03 -
Add the egg and vanilla extract to the creamed mixture and continue beating until fully combined.
04 -
Gradually mix in the flour, cocoa powder, baking soda, and salt until just incorporated, scraping down the sides as needed.
05 -
Fold in the chocolate chips and white chocolate chips by hand to maintain texture.
06 -
Transfer the dough into the prepared pan and bake for 25 minutes or until set with a golden brown top. Cool to room temperature.
07 -
Combine heavy cream and chopped chocolate in a microwave-safe bowl. Heat in 30-second intervals, stirring until smooth. Add a pinch of salt and whip using a mixer or immersion blender on medium speed until it holds a pipeable shape.
08 -
Remove the cooled cookie cake from the pan and spread or pipe the whipped ganache evenly on top. Optionally decorate with additional chocolate chips or sprinkles.