Spray a 9" springform pan liberally with baking spray. Set aside.
In a large bowl, whisk together the butter, sugar, eggs, and vanilla.
Add the cocoa powder, flour, salt, and baking powder and stir until a thick batter forms.
Spoon the batter evenly into the bottom of a 9" springform pan.
Bake in a preheated oven for 30 minutes.
Remove and allow the brownie to cool completely before proceeding with the ice cream layers.
To add the ice cream layers:
Soften one of the half gallons of ice cream slightly (5-7 minutes at room temperature).
Spread the ice cream over the cooled brownie bottom and smooth evenly over the entire surface.
Return the ice cream cake back to the freezer for an additional 40 minutes.
Soften the remaining half gallon of ice cream and spread that evenly over the frozen ice cream cake.
Return the Neapolitan ice cream cake to the freezer until ready to garnish and serve.
To serve Neapolitan Ice Cream Cake:
Allow the cake to sit at room temperature to soften slightly.
Run a hot knife (dip the blade in hot water and dry) around the inside of the springform pan to losen.
Lift the springform cake collar up carefully and evenly over the cake.
To garnish, sprinkle a light dusting of cocoa powder and confectioners sugar on top of the ice cream cake. Add fresh strawberries if desired.
Serve and enjoy.
Video
Notes
This ice cream cake can be made in advance and kept in the freezer for up to 2 weeks. I suggest covering it well, and leaving the springform collar in place while in the freezer.