Line the bottom and sides of a 9-inch square cake pan with parchment paper and set aside.
Combine the cranberries, sugar and water in a saucepan. Cut the vanilla bean in half horizontally and scrape the black seeds into the cranberry mixture. Add the bean. Place the pan over medium-high heat and bring to a boil, stirring occasionally. Reduce heat and continue simmering until the cranberries are soft, but not falling apart, 5-7 minutes.
In a bowl, combine the egg yolks, water and 2 tablespoons sugar. Cut the vanilla bean in half horizontally and scrape the black seeds into the yolk mixture. Add the bean. Place the bowl over a pot of simmering water and whisk constantly until the mixture thickens and registers 160F on an instant-read thermometer. Remove from heat and place over a bowl of ice water to cool completely. Once cool, remove the vanilla bean.
In a separate bowl, beat the egg whites to soft peaks. Gradually add the remaining 1/4 cup sugar and beat until stiff.
Combine the cranberry compote and the cooled yolk mixture, then fold in the beaten egg whites. In a separate bowl, whip the cream until stiff then fold into the cranberry mixture.
Spread evenly in the prepared pan. Cover the top with parchment paper and freeze overnight.
Combine all sorbet ingredients in a saucepan. Place over medium-high heat and bring to the boil, stirring occasionally. Reduce heat and continue simmering until the cranberries are very soft, 6-8 minutes. Remove from heat and cool slightly.
Puree the mixture in a blender and strain through a fine mesh strainer. You should be left with about 4 cups of liquid. If not, top up with a little more cranberry juice. Chill the mixture thoroughly then freeze in an ice cream freezer according to the manufacturer’s instructions. (If you don’t have an ice cream machine, a good-quality store-bought raspberry sorbet would work as well; thaw slightly, then follow steps 3 and 4.)
Spread the sorbet evenly over the semifreddo, cover and freeze until firm.
Once the semifreddo is firm, it can be removed from the pan and cut into individual servings. Cover well and return to freezer until serving time.
Toasted Almond Meringue
Preheat oven to 300F. Have ready, two sheets of parchment paper to fit two 11-by-17-inch baking sheets.
Sift 2 tablespoons granulated sugar with icing sugar. Stir in toasted, chopped almonds and set aside.
Place egg whites in a clean, dry bowl of an electric mixer. Using the whisk attachment beat on high speed just until frothy. Sprinkle in 2 tablespoons granulated sugar and beat to soft peaks. Gradually add the remaining 1/3 cup granulated sugar and continue beating until the whites are stiff and glossy and all the sugar has dissolved.
Remove the bowl from the mixer and add about half the nut mixture. Fold in with a rubber spatula just until incorporated. Repeat with remaining nut mixture.
With an off-set metal spatula, spread the meringue thinly and evenly over each of the two pieces of parchment paper. Transfer the parchment onto the baking sheets and bake the meringue for 1 hour or until crisp. (The meringue will take on some colour.)
Cool completely. Break into large shards and store in an airtight container at room temperature.
Crush some of the almond meringue in small pieces and place onto each serving plate. Place a portion of semifreddo on top of meringue. Spoon a quenelle of whipped cream onto each serving and arrange shards of meringue on cream. Dust lightly with icing sugar. Place fresh raspberries or poached cranberries around the semifreddo, garnish with lemon balm or mint leaves and serve.