Preheat oven to 350 degrees. Lightly grease a 9” springform pan with cooking spray. Set aside.
Place a small saucepan half filled with water over medium heat and bring to a simmer. Combine bittersweet chocolate and butter in a heatproof bowl and place over the pot. Stir until chocolate and butter are completely melted. Turn off heat and set chocolate mixture aside.
Completely dissolve espresso powder in warm water. Add sugar and espresso to melted chocolate, stir until completely combined; slightly cool. Add eggs, whisking until completely blended. Stir in cocoa powder.
Pour batter into a prepared springform pan. Bake until set in the middle and a thin crust forms on top, approximately 30 minutes. Remove cake from oven and cool for approximately 15 minutes. Gently remove the sides of the springform pan. Cool completely.
To make the ganache, pour cream into a small saucepan. On low heat bring cream to a simmer, add chocolate chips and stir until melted and blended. Pour over the cake and spread with a spatula. Allow ganache to set, garnish with raspberries and mint. Serve.