For Citrus Base
Scented Red Berries
Prepare a 9-inch square pan by lining bottom and sides with plastic wrap, having wrap hang over edges of the pan.
For citrus base, bring lemon juice, lime juice, both zests and cream just up to a simmer in a saucepot. In a bowl, whisk egg yolks with sugar and cornstarch. Slowly add some of the cream to the egg mixture, whisking constantly, and keep adding cream until it has been fully blended into the eggs. Return mixture to the stove and cook over medium heat, whisking constantly until thickened and glossy, only about 2 to 3 minutes. Remove from heat and strain. Soften gelatin in cold water for 2 minutes, then whisk into hot custard. Set aside to cool at room temperature (do not chill).
For meringue, bring sugar and water to a boil and cook on high heat until sugar registers 240 °F on a candy thermometer, about 3 minutes. While sugar is boiling, whip egg whites until they hold a soft peak (bend when whisk is lifted). Slowly and carefully pour in hot sugar down the side of the bowl with the meringue, whipping constantly (pouring it down the side of the bowl will prevent splashes of hot sugar), and whip the whites on medium speed until they have cooled to barely warm. Fold a third of the meringue into the citrus base and then fold in the remaining two thirds until incorporated. Scrape mousse into prepared pan and spread evenly. Chill until firm, about 4 hours.
To serve, turn mousse out onto a plate and peel off plastic. Cut into squares and place over Scented Red Berries
Toss strawberries, raspberries and currants gently. Stir red currant jelly with sugar and zests and toss with berries to coat.
Berries can be prepared up to 2 hours in advance and chilled until ready to serve.