- 2 cups sweetened flaked coconut
- 1 1/2 teaspoons cornstarch
- 1/2 teaspoon vanilla extract
- 2 tablespoons (1/4 stick) unsalted butter, cut into small pieces, room temperature
- 4 ounces bittersweet or semisweet chocolate chips (about 2/3 cup)
- 3/4 cup chilled whipping cream
- 2 bananas, cut into 1/4-inch-thick rounds
Position rack in center of oven and preheat to 350°F. Spread 11/2 cups coconut on large baking sheet. Toast until golden, stirring twice, about 15 minutes. Cool. Maintain oven temperature.
Line another large baking sheet with foil. Using electric mixer, beat egg whites and next 4 ingredients in large bowl until foamy. Gradually add sugar and beat until stiff peaks form. Beat in 1/4 cup boiling water, 1 tablespoon at a time, beating until whites are stiff and glossy. Fold in 1 cup toasted coconut. Spoon meringue onto center of prepared baking sheet and spread to 9-inch-diameter circle with slightly raised edges. Sprinkle with remaining 1/2 cup untoasted coconut.
Bake meringue 10 minutes. Reduce oven temperature to 200°F and bake until dry and crisp outside and just cooked through inside, about 1 hour. Turn off oven. Let meringue stand in oven 1 hour. Remove from oven and cool completely.
Whisk egg yolks, 2 tablespoons sugar, butter, 2 tablespoons water, and rum in medium metal bowl to blend. Set bowl over saucepan of simmering water (do not allow bottom of bowl to touch water). Whisk until thermometer inserted into mixture registers 160°F, about 6 minutes. Add chocolate and whisk until melted and smooth. Turn off heat; leave bowl over water.
Using electric mixer, beat egg whites in large bowl until soft peaks form. Gradually add 2 tablespoons sugar and beat until stiff peaks form. Fold 1/3 of egg whites into chocolate mixture to lighten. Fold in remaining whites. Remove from over water and let mousse cool 20 minutes.
Beat whipping cream in large bowl until peaks form. Place meringue on platter. Spread mousse over center of meringue; top with sliced bananas. Spread whipped cream over bananas and chill at least 20 minutes and up to 3 hours.
Sprinkle with remaining toasted coconut. Cut into wedges and serve.