Neapolitan Pistachio Frozen Bombe

Grease 8-inch (2 L) springform pan; set pan aside.

Cake: In bowl, beat egg and egg yolk until foamy. Gradually beat in sugar; beat until batter falls in ribbons when beaters are lifted, about 3 minutes. Beat in vanilla. In small bowl, whisk flour, baking powder and sa< sift half over egg mixture and fold in. Repeat with remaining flour mixture.

Transfer one-quarter of the batter to small bowl; fold in butter. Pour back over batter; sprinkle with pistachios and fold in. Scrape into prepared pan. Bake in centre of 325°F (160°C) oven until cake springs back when lightly touched, about 30 minutes. Let cool in pan on rack for 10 minutes. Turn out onto rack; let cool completely.

Let chocolate and strawberry ice creams stand at room temperature for about 20 minutes or until soft enough to scoop. Line 7-1/2-inch (1.5 L) bowl with plastic wrap, leaving 3-inch (8 cm) overhang. Line bowl with strawberry ice cream, spreading in even layer. Fill with chocolate ice cream, smoothing top. Trim cake to fit bowl; place over ice cream, pressing gently. Cover with plastic wrap; freeze for 3 hours or until firm. (Make-ahead: Freeze for up to 24 hours.)

Place chocolate in bowl. In small saucepan, bring cream to boil; pour over chocolate and whisk until smooth. Let cool for 10 minutes.

Remove plastic wrap from top of bombe. Invert bowl onto rack over rimmed baking sheet; remove bowl and peel off wrap. Starting at top of dome, pour chocolate mixture over cake in spiral motion, spreading with palette knife to cover completely and letting excess drip off. Sprinkle bottom edge with pistachios. Freeze for at least 15 minutes or until set. (Make-ahead: Wrap in plastic wrap and heavy-duty foil; freeze for up to 2 weeks.)

Transfer bombe to flat serving plate. Let stand in refrigerator for 10 minutes before cutting.