To Prepare the Swiss Meringue:
Fill a medium saucepan up 2/3 full of water and bring it to a boil. Put the heatproof bowl of your stand mixer over the saucepan and whisk together the egg whites, sugar, and cream of tartar until the sugar is dissolved. Put the bowl under your stand mixer fitted with a whisk and beat on high until firm and glossy. Whisk in the vanilla extract. Let cool completely to room temperature.
To Prepare the Baked Alaska:
Unmold the ice cream bombe over a heat-proof platter or pan. Spread or pipe the meringue on the ice cream bombe and use an offset spatula to form peaks and make it rustic looking. Use a blow-torch to brown the tips of the meringue, slice, and serve.