Preheat your oven to 350 degrees F. and prepare a 8” springform pan with nonstick spray and line the bottom with aluminum foil.
Prepare the cake batter by combining all dry ingredients into the bowl of a stand mixer or large mixing bowl.
Add in the eggs, oil, vanilla, and milk mix until well combined. Be sure to scrap the bowl to make sure everything is combined.
Carefully add in boiling water last. Mix on slow until everything Is combined and then increase speed to high for one minute.
Pour the batter into the prepared springform and bake for 35-40 minutes or until you can insert a toothpick and it comes out clean.
Let the cake cool completely. I took off the ring of the springform pan and then I leveled my cake, then placed the ring back on. (this is optional, BUT it will give you a better appearance after you add the mousse layer. )
Next, prepare the mousse layer by adding 1 ½ tbsp water into a small bowl and sprinkle with the gelatin powder and set aside.
Combine ½ cup of the heavy cream and the Bailey’s Irish cream into a microwave safe bowl and heat for 1 minute. Add in chocolate chips and set aside for a few minutes to allow the chocolate to melt. Mix until smooth.
Add the remaining 1 ½ cup of heavy cream into the bowl of stand mixer with a whisk attachment. Mix on medium speed, add in the confectioners sugar. Mix until thick and stiff peaks form.
Slowly add in the Bailey’s ganache half at a time, whipping on a high speed until well combined and fluffy. Pour mixture on top of the cake and place in the refrigerator for at least 6 hours or overnight to allow it to set.
Top with your favorite toppings and enjoy!!