Heat oven to 350°F. Line an 8×8-inch square baking pan with parchment paper. Spray parchment with cooking spray.
In a small saucepan over medium heat, melt butter, cocoa powder and chopped chocolate, stirring constantly, 4 to 5 minutes until melted and smooth. Remove from heat; set aside to cool.
In a large bowl using a hand mixer or in the bowl of a stand mixer with the paddle attachment, beat sugars and eggs together on medium-high speed 3 to 4 minutes until mixture is pale and thickened. Gently stir in vanilla, then cooled butter-chocolate mixture. Fold in flour and salt until just combined.
Gently fold in chopped cherries and chocolate chips until just combined. Pour batter into prepared baking pan.
Bake 35 to 40 minutes or until a toothpick inserted near center of brownies comes out clean or with moist crumbs clinging (do not overbake). Cool brownies in pan on a cooling rack completely, about 1 hour.
Remove brownies from baking pan. Use a sharp serrated knife to gently saw brownies into rows, 4×4, to make 16 total squares.
In a medium bowl, beat heavy cream with a hand mixer on medium-high speed 3 to 4 minutes until stiff peaks form. Spoon a generous dollop of whipped cream on top of each brownie just before serving, if desired. Garnish with more grated chocolate and a cherry, if desired.