Preheat your oven to 350°F (175°C) and prepare a baking pan with nonstick spray and parchment paper.

Melt the unsalted butter in a saucepan over low heat, whisk in Dutch-process cocoa powder and chopped bittersweet chocolate until smooth.

Combine granulated sugar, light brown sugar, eggs, and vanilla extract in a bowl and whisk until frothy.

Mix the melted chocolate into the egg mixture until well combined.

Whisk together flour, baking powder, and salt. Fold into the brownie batter until just combined.

Spread the batter in the prepared pan and bake for 25-28 minutes, until a toothpick comes out with moist crumbs.

Allow the brownies to cool in the pan on a wire rack.

Heat heavy cream in a saucepan, then pour over chopped bittersweet chocolate. Let sit, then stir until smooth.

Spread the ganache over the cooled brownies and sprinkle with candy-coated sprinkles.

Refrigerate for at least 30 minutes, cut into squares, and serve.