1 pint raspberry sorbet, divided and slightly softened
1¼ cups vanilla ice cream, slightly softened
½ cup all-purpose flour
½ teaspoon kosher salt
¼ teaspoon ground cinnamon
⅛ teaspoon ground ginger
3 large egg yolks
⅓ cup mashed ripe banana (1 small banana, frozen in its skin for a few hours and thawed)
5 tablespoons sugar, divided
2 large egg whites
1 teaspoon vanilla extract
¼ cup chopped walnuts
⅓ cup apricot jam
4 large egg whites
¾ cup sugar
¼ teaspoon cream of tartar
½ teaspoon vanilla extract
Pinch kosher salt
2 tablespoons alcohol (such as Bacardi 151)
Directions
Make the ice cream mold: Grease a medium bowl with an 8-inch diameter (such as a 1½-quart-capacity Pyrex glass bowl) with cooking spray and double-line with plastic wrap, allowing the wrap to hang 8 inches over one end. Pack and evenly smooth the base with ¾ cup raspberry sorbet, then layer with the vanilla ice cream, and finish with the remaining raspberry sorbet. Cover the ice cream with the plastic wrap overhang and freeze until firm, at least 2 hours, preferably overnight.
Meanwhile, make the cake: Preheat the oven to 350°. Grease the inside of an 8-inch cake pan with cooking spray, line the bottom with parchment paper and grease the paper as well; set aside.
In a small bowl, whisk together the flour, salt, ground cinnamon and ground ginger; set aside.
In a large bowl, beat the egg yolks, banana and 3 tablespoons of the sugar until thick and pale, 1 minute, and set aside.
In the bowl of a stand mixer fitted with a whisk attachment, beat the egg whites on medium speed until foamy. Increase the mixer speed to medium high and, with the mixer running, gradually add the remaining 2 tablespoons of sugar and vanilla. Increase the mixer to high speed until medium peaks form, about 3 minutes total.
Gently fold the egg whites into the egg yolk mixture, then fold in the flour mixture and chopped walnuts, stirring until just combined. Pour the batter into the prepared baking pan, smooth the top with the back of a spoon or small offset spatula, and bake until light golden brown, 15 to 18 minutes. Run an offset spatula or butter knife along the golden brown edges of the cake to release it from the sides of the pan and invert it onto a resting rack; let cool completely, 30 minutes. Note: If you are in a time crunch, let the cake cool on the resting rack in the freezer for 15 minutes.
When the cake is cooled, make the Swiss meringue: Fill a medium saucepan with water to a 1-inch depth and bring to a simmer over medium heat.
In the bowl of an electric mixer, combine the egg whites, sugar and cream of tartar, and place over the saucepan. Whisk constantly until the sugar is dissolved and the whites are warm to the touch, or a candy thermometer reads 145°, 3 to 3½ minutes. Wipe the outside bottom of the bowl dry and transfer to an electric mixer fitted with a whisk attachment. Add the vanilla and salt, and whip on low speed, gradually increasing to high speed, until stiff and glossy peaks form, 7 to 10 minutes. Makes 5 cups Swiss meringue.
Assemble the Baked Alaska: Remove the ice cream mold from the freezer and unwrap the top plastic, exposing the raspberry sorbet. Spread the apricot jam over the top side of the cake and place the cake onto the raspberry sorbet, with the jam layer touching the sorbet, gently pressing to adhere. Freeze 10 minutes.
Remove the chilled ice cream cake from the freezer and lift it out of its bowl. Invert it onto a cake stand or large serving plate, so the banana cake is the base. Peel away and discard the plastic wrap.
Working quickly, pile the Swiss meringue onto the cake and frost it using an offset rubber spatula. Using a kitchen blowtorch, toast the entire frosted cake, except for the very top, until the meringue is light golden brown. Pour the alcohol over the very top of the cake, letting it drip around the sides, and carefully light on fire with the blowtorch, toasting the meringue. Cut into slices and serve immediately.