Make the meringue only after your ice cream and brownie are frozen. Mix granulated sugar and cream of tartar until the cream of tartar has disappeared into the sugar. Place in top of a double boiler and add your room temperature egg whites. Over simmering water, cook stirring constantly with a whisk until mixture reaches 160’ (takes about 15 minutes). Immediately pour hot egg whites into your mixer. Beat at high speed for 5 minutes, or until soft peaks form. Remove ice cream from the freezer, invert and peel off the foil. Set ice cream on top of frozen brownie layer. Immediately spread meringue over entire surface, making sure all of the ice cream is covered. Freeze at least 4 hours. Note: At this point, you can wrap your Baked Alaska and keep in the freezer for one month.