01 - Preheat oven to 350°F. Grease a 9-inch springform pan and line bottom with parchment paper.
02 - In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt until well combined.
03 - Add milk, vegetable oil, eggs, and vanilla extract to the dry mixture. Beat until smooth, then stir in hot water until fully incorporated (batter will be thin).
04 - Pour batter into prepared springform pan. Bake for 22 to 25 minutes until a toothpick inserted in center comes out clean. Cool completely in the pan.
05 - Spread softened mint chocolate chip ice cream evenly over the cooled cake. Smooth surface with an offset spatula. Freeze for at least 3 hours until firm.
06 - Heat heavy cream in a saucepan until just simmering. Pour over chocolate chips in a heatproof bowl. Let stand for 2 minutes, then stir until completely smooth and glossy.
07 - Allow ganache to cool slightly until thickened but still pourable. Pour over frozen ice cream layer and spread evenly. Return to freezer for 30 minutes to set.
08 - Garnish with mini chocolate chips and fresh mint leaves if desired. Run a warm knife around pan edge, release springform, and slice immediately.