Place vanilla ice cream in the refrigerator for about 2 hours to soften a bit. Line mold with plastic wrap in contact. Fill up mold to the top with vanilla ice cream and freeze for 6 hours or more. Dig out a 1.5 to 2''/ 5cm trench going back and forth using an ice cream scoop; freeze for a few hours. Fill the channel two-third up with the raspberry sorbet and freeze until it has hardened. Finish covering the gap with more vanilla ice cream and freeze the log for 24 hours. Remove from mold and keep frozen.
Make a 15''x21''/37.5x52cm baking tray lined with greased parchment or silicon mat. In a mixing bowl, beat room temp egg whites and one-third of the sugar on high speed. Continue beating to firm peaks adding remaining sugar gradually. Transfer meringue in a separate bowl. No need to clean the mixing bowl. Gather almond meal with powdered sugar, flour and eggs on high speed for 5 min on high speed. Fold in one-third of the meringue first and add remaining meringue and the melted butter. Spread Joconde batter evenly using a large offset spatula.
Bake at 450ºF/230ºC for about 7 min using a convection oven or 10 min in conventional oven. Do not over bake the biscuit Joconde sheet or it will lose its flexibility. Let cool to room temp, wrap up and refrigerate.
Remove frozen ice cream log; keep frozen. Meanwhile, unwrap Joconde biscuit, run a knife around the edges of the sponge to loose it up. Place a silicone mat on top and flip. Carefully, remove the parchment paper. Cut out a 4''x10''https://bruno.b-cdn.net/ 10x25cm rectangle for the bottom Joconde. Cut a 7.5''/19x10''/25cm rectangle for the top. Save leftover biscuit for later use. Place the bottom Joconde biscuit onto a rectangular serving tray. Place the hard frozen ice cream on top and dress the log with the second Joconde sheet and freeze. At this juncture, the cake can be wrapped up and kept frozen for weeks prior being finished.
Beat room temp egg whites and one-third of the sugar on high speed. Continue beating until fluffy and smooth adding remaining sugar gradually. Transfer meringue in a large separate bowl. Do not clean the mixing bowl – beat egg yolks, vanilla and sugar on high speed for 5 minutes using the whisk attachment. Combine both mixtures. Coat the frozen ice cream cake and keep frozen. Blow-torch the cake right before serving or bake it in a 450ºF/230ºC oven for a few minutes. Heat up some Grand Marnier, Cognac or old dark rum, ignite it and pour over the baked Alaska. Enjoy!