1. Whisk 1 1/3 cups sugar, 1/4 cup water, 1/4 cup rum, 3 tablespoons brandy, yolks, and nutmeg in metal bowl.
2. Set bowl over saucepan of simmering water (do not allow bottom of bowl to touch water). Whisk constantly until mixture thickens and candy thermometer inserted into mixture registers 140°F for 3 minutes, about 5 minutes total.
3. Remove bowl from over water. Whisk mascarpone, 1 container at a time, into warm custard until blended.
4. Using electric mixer, beat whipping cream, vanilla, 1 tablespoon brandy, and 1 teaspoon rum in large bowl until cream holds peaks. Fold in mascarpone mixture.
5. Bring 1 cup water to simmer in small saucepan. Remove from heat. Add 2 tablespoons sugar and espresso powder; stir to dissolve. Mix in liqueur.
6. Submerge 1 biscuit in espresso mixture, turning to coat twice; shake excess liquid back into pan. Place dipped biscuit, sugared side facing out, around bottom side of 14-cup trifle dish, pressing against side of dish (biscuit may break). Repeat with enough biscuits to go around bottom sides of dish once. Dip more biscuits and arrange over bottom of dish to cover.
7. Spoon 2 cups mascarpone mixture over biscuits; spread to cover. Sprinkle 1/4 cup ground chocolate over, making chocolate visible at sides of dish. Repeat with more biscuits dipped into espresso mixture, mascarpone mixture, and ground chocolate in 2 more layers each. Cover with 1 more layer of dipped biscuits and enough mascarpone mixture to reach top of trifle dish. Sprinkle remaining ground chocolate over, covering completely. Cover and chill overnight.
8. Gently press stem end of largest chocolate leaves around edge of trifle. Fill center with smaller leaves. (Can be made 8 hours ahead; chill.)

Serves 16-18.

*Available at Italian markets, specialty foods stores, and some supermarkets.

Chocolate Leaves [2]

8 ounces bittersweet (not unsweetened) or semisweet chocolate, chopped
40 assorted sizes of camellia leaves or lemon leaves, wiped clean
Gold dust* (optional)

1. Line large baking sheet with foil.
2. Melt chocolate in top of double boiler over simmering water, stirring until smooth and instant-read thermometer inserted into chocolate registers 115°F. Brush chocolate over veined side (underside) of 1 leaf, coating thickly and completely. Arrange chocolate side up on prepared baking sheet.
3. Repeat with remaining leaves and chocolate, rewarming chocolate if necessary to maintain 115°F temperature. Chill leaves until firm, about 45 minutes.
4. Starting at stem end, carefully pull back green leaf, releasing chocolate leaf; return leaves to same baking sheet. (Can be made 2 days ahead. Cover and keep chilled.) Using small artist brush, carefully brush some leaves with gold dust, if desired.

Makes about 40 leaves.

*Available at cake and candy supply stores, or by mail from Jane's Cakes and Chocolates at 800-262-7630.