This impressive ice-cream dessert makes the most of summer fruit. This recipe calls for lining the entire mold with raspberries, which is best done when berries are in season, but this step can be skipped and berries used only on the inside.
Preheat oven to 200 degrees. Line a baking sheet with parchment; set aside. In the bowl of an electric mixer, combine egg whites, sugar, and cream of tartar. Set over a pan of simmering water; whisk constantly until sugar is dissolved and mixture is warm to the touch. Remove from heat; mix, using whisk attachment, on medium high, until stiff peaks form, about 10 minutes.
Transfer meringue to parchment-lined baking sheet; spread into a 5-inch-diameter disk that is 1/2 inch thick. Transfer to oven; let dry but not brown; this will take about 4 hours. Remove from oven; let cool. Remove from parchment, break into 2- to 4-inch shards, and set aside.
Meanwhile, line a 9-inch-diameter, 4- inch-deep metal bowl with raspberries. With open sides of berries facing wall of bowl, place raspberries neatly in bottom and up sides of bowl. Work up sides of the bowl as far as you can; if berries start to fall, add them later. Transfer the bowl to the freezer, and let berries completely freeze to the bowl, about 2 hours.
Beat 1 cup raspberry sorbet in the bowl of an electric mixer fitted with the paddle attachment until soft but still holding its shape, 1 to 2 minutes. Remove the mold from the freezer, and gently layer sorbet in bottom of bowl, smoothing it toward the edges with an offset spatula. Return mold to freezer until sorbet has hardened. Remove mold from freezer; cover the sorbet with a single layer of raspberries, about 1 1/2 cups. Return to freezer until berries are solid, about 20 minutes. Soften 1 pint vanilla ice cream as above. Remove mold from freezer; spread a layer of vanilla ice cream over frozen berries, making sure ice cream is spread all the way to the sides of the berry-lined bowl. Return mold to freezer, and let vanilla ice cream become firm, about 15 minutes.
Soften 1 pint raspberry sorbet as above; set aside. Remove mold from freezer; layer the meringue on top of the vanilla ice cream in a single layer; it is fine if some pieces overlap. On top of the meringue, spread the remaining cup of raspberry sorbet, making sure it touches berrylined edges of the bowl. Return mold to freezer. Continue process with one more single layer of raspberries, about 2 cups. Add remaining softened vanilla ice cream in an even layer. Add berries as needed to bowls lining so they completely encase the ice cream to top of bowl. Cover with plastic wrap; let bombe completely freeze overnight. Scatter sliced almonds, if using, over vanilla ice cream to keep from slipping when turned out. To unmold, dip bowl into very hot water for 7 seconds. Using some force, invert onto a cutting board. Transfer to serving platter. Working quickly, using a sharp knife, slice bombe into wedges; serve.