4 large (best looking) naval oranges
7 oz semisweet chocolate
1 oz unsweetented chocolate
1/2 cup whipping cream, chilled
3 eggs, separated, room temperature
1/4 cup sugar
3 Tb Grand Marnier
pinch cream of tartar
Fresh mint leaves and whipped cream for garnish

Cut oranges in half through stem ends. Carefully remove all pulp with spoon. Trim excess white membranes from around edges to make smooth cup.

Melt chocolate in double boiler. Remove from over water and stir until smooth. Let cool a bit.

Meanwhile, beat yolks with sugar in large bowl until light and fluffy, about 5 minutes. Mix in liqueur.

Whip chilled cream in medium bowl to soft peaks.

Beat whites with cream of tartar in another large bowl until just stiff but not dry.

Gently fold cooled chocolate into yolk mixture, then fold in whites half at a time. Fold in cream.

Set orange shells in muffin pan, or arrange (leaning on one another) on cookie sheet. Spoon chocolate mousse into each half, just to top. Freeze until firm, about 2 hours.

Place oranges on cutting board, mousse side down, and quickly slice each into 2 or 3 equal wedges using long sharp knife dipped into hot water and dried between each cut. If desired, smooth sides with small knife dipped in hot water and dried. Refrigerate. Bring to room temperature for serving and, garnish with mint and serve with whipped cream.