Frozen Chocolate-Peppermint Bùche de Noël

Ingredients:
8 ounces bittersweet chocolate (do not exceed 61% cacao), chopped
3/4 cup heavy whipping cream
3 ounces bittersweet chocolate (do not exceed 61% cacao), chopped
10 fresh camellia leaves or lemon leaves, wiped clean with damp cloth
Nonstick vegetable oil spray
1 cup sugar, divided
3/4 cup cake flour
1/4 cup natural unsweetened cocoa powder
1 teaspoon baking powder
1/4 teaspoon salt
4 large eggs, separated
2 tablespoons vegetable oil
2 tablespoons water
1 teaspoon vanilla extract
1/8 teaspoon cream of tartar
2 pints peppermint stick ice cream
1/3 cup coarsely crushed red-and-white-striped hard peppermint candies or candy canes
5 large egg whites
1/4 teaspoon cream of tartar
3/4 cup sugar
1/2 teaspoon vanilla extract
Fresh mint sprigs
Small candy canes
Small propane kitchen torch

Instructions:
Place chocolate in medium microwave-safe bowl. Bring cream to simmer in small saucepan. Pour cream over chocolate. Let stand 1 minute, then whisk until melted and smooth. Do ahead can be made 1 week ahead. Cool, cover, and chill. Rewarm, uncovered, in microwave in 15-second intervals and whisk before using.
Stir chocolate in small saucepan over low heat until melted and smooth. Remove from heat. Using pastry brush, brush chocolate on underside (veined side) of 1 leaf to coat completely (do not allow chocolate to drip over edge of leaf). Place leaf, chocolate side up, on small foil-lined baking sheet. Repeat with remaining leaves. Chill, uncovered, until chocolate coating is cold and firm, at least 1 hour. Working with 1 leaf at a time, carefully peel green leaf away from chocolate. Return chocolate leaf to same sheet; discard green leaf. DO AHEAD: Can be made 3 days ahead. Cover with plastic wrap and chill.
Position rack in center of oven and preheat to 375°F. Line 15 x 10 x 1-inch baking sheet with parchment. Coat paper with nonstick spray and dust with cocoa.
Sift 1/2 cup sugar, cake flour, 1/4 cup cocoa, baking powder, and salt into small bowl. Using electric mixer, beat egg yolks in large bowl until thick. Beat in oil, 2 tablespoons water, and vanilla. Gradually add dry ingredients, beating just until blended. Using clean dry beaters, beat egg whites and cream of tartar in medium bowl until soft peaks form. Gradually add remaining 1/2 cup sugar, beating until stiff but not dry. Fold 1/4 of whites into yolk mixture to lighten. Fold in remaining whites in 2 additions. Spread batter evenly on prepared baking sheet.
Bake cake until puffed and tester inserted into center comes out clean, about 12 minutes. Cool cake in pan on rack 10 minutes. Sift light layer of cocoa over large smooth kitchen towel (not terry cloth). Cut around pan sides. Turn cake out onto prepared towel, leaving 3-inch cloth border on 1 long side. Peel off parchment. Starting at long side with cloth border and using cloth as aid, roll up cake in towel (towel will be rolled up inside). Place cake, seam side down, on work surface; cool completely.
Microwave ice cream in 10-second intervals until barely softened. Unroll cake on work surface but leave on cloth. Dollop ice cream over cake by spoonfuls. Gently spread ice cream into even layer, leaving 1-inch plain border on long side opposite cloth border. Sprinkle ice cream with crushed candy. Using cloth as aid and starting at cloth border, roll up cake, enclosing ice cream in cake. Place cake, seam side down, on long platter; cover with plastic wrap. Freeze cake at least 8 hours or overnight.
Using electric mixer, beat egg whites and cream of tartar in large bowl to soft peaks. Gradually add sugar, beating until stiff but not dry. Beat in vanilla.
Cut off 1/8 of cake at angle at 1 end. Press cutoff part onto center of 1 side of log, cut side in. Spread meringue all over top, sides, and ends of cake. Using fork, make long grooves in meringue down length of cake and in circles on ends to resemble tree bark. Freeze cake until meringue is cold and firm, at least 3 hours. Using torch, brown meringue in random spots. Return cake to freezer. DO AHEAD: can be made 2 days ahead. Cover and keep frozen.
Garnish cake with chocolate leaves, fresh mint sprigs, and small candy canes. Cut cake crosswise into 1-inch-wide slices. Drizzle with warm chocolate sauce.