01 - Preheat oven to 350°F. Grease and line a 9-inch springform pan 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, oil, eggs, and vanilla extract to the dry mixture. Mix until combined, then stir in hot water until smooth. The batter will be thin.
04 - Pour batter into the prepared pan. Bake for 22 to 25 minutes or until a toothpick inserted in the center comes out clean. Cool completely in the pan.
05 - Once the cake is cool, spread softened mint chocolate chip ice cream evenly over the cake layer. Smooth the surface and freeze for at least 3 hours, or until firm.
06 - Heat heavy cream until just simmering, then pour over chocolate chips. Let sit for 2 minutes, then stir until smooth and glossy.
07 - Let ganache cool slightly, then pour over the frozen ice cream layer, spreading evenly. Freeze for 30 minutes more.
08 - Garnish with mini chocolate chips and mint leaves if desired. Run a warm knife around the edge of the pan, release the springform, and slice.