180°C, 350°F, Gas Mark 4
Serves 50

Ingredients for Cake Layers
 

Butter one 12-inch diameter cake pan with 3-inch high sides, one 9-inch diameter cake pan with 3-inch high sides and one 7-inch diameter cake pan with 3-inch sides. Line bottoms with parchment. Sift flour, baking powder and salt into medium bowl. Using an electric mixer, beat butter in a 12-quart bowl on medium-high speed until light. Gradually add sugar and beat until well blended. Beat in extracts. On medium-low speed, beat in dry ingredients alternately with milk in 3 additions each, beating just until combined (batter will be thick).

Using an electric mixer fitted with clean, dry beaters, beat whites in another large bowl until stiff but not dry. Fold 1/3 of whites into batter to lighten. Fold in remaining whites. Spoon batter into prepared pans so that depth of batter is the same in each pan; smooth tops. Bake until tops are deep, golden brown and tester inserted into centre comes out clean - about 55 minutes for 6-inch cake, 1 hour 5 minutes for 9-inch cake and 1 hour 20 minutes for 12-inch cake. Cool cakes in pans on racks for 20 minutes. Run knife around pan sides to loosen cakes. Turn out cakes onto racks and peel off parchment. Cool cakes completely.

For the Soaking Syrup:
Mix all ingredients in heavy, large saucepan. Boil over medium-high heat until mixture is reduced to 2 2/3 cups, stirring occasionally - about 10 minutes. Cool syrup completely.

For the Frosting:
Using an electric mixer, beat cream cheese in large bowl until light. Gradually add sugar and beat until fluffy. Add cream, Marsala and vanilla and beat until well blended. Cover and let stand at room temperature for up to 1 hour.

Assembly:
Finely grind chopped chocolate in processor (do not over-process or chocolate will clump together). Using a serrated knife, cut each cake horizontally into 3 equal layers. Spread dab of frosting on 6-inch cardboard round; top with bottom layer of 6-inch cake, cut side up. Brush cakes with 2 tablespoon syrup. Spread ½ cup frosting over. Sprinkle with 2 tablespoons ground chocolate. Brush 2 tablespoons syrup over cut side of top 6-inch cake layer. Using hands, turn layer over and place cut side down on top of frosted layers. Cover and refrigerate cake.

Spread dab of frosting on 9-inch cardboard round; top with bottom layer of 9-inch cake, cut side up. Brush with ¼ cup syrup. Spread ½ cup frosting over. Sprinkle with ¼ cup ground chocolate. Top with middle 9-inch cake layer. Brush with ¼ cup syrup. Spread 1 cup frosting over. Sprinkle with ¼ cup ground chocolate. Brush ¼ cup syrup over cut side of top 9-inch cake layer. Slide large tart-pan bottom or spring form cake-pan bottom under cake layer. Using pan bottom as an aid, lift cake layer and turn cut side down on top of frosted layers. Cover and refrigerate cake. Spread dab of frosting on 12-inch cardboard round; top with bottom layer of 12-inch cake, cut side up. Brush with ½ cup syrup. Spread 2 cups frosting over. Sprinkle with ½ cup ground chocolate. Top with middle 12-inch cake layer. Brush with ½ cup syrup. Spread 2 cups frosting over. Sprinkle with ½ cup ground chocolate.

Brush ½ cup syrup over cut side of top 12-inch cake layer. Slide large tart pan bottom or cake pan bottom under cake. Using pan bottom as aid, lift cake layer and turn cut side down on top of frosted layers. Cover cake; refrigerate all cakes until firm - about 4 hours. Cover remaining frosting and let stand at room temperature. Place 12-inch cake on its cardboard on large, flat platter. Place platter on cake stand. Using icing spatula, spread 4 cups frosting over top and sides of cake; smooth top. Swirl frosting decoratively on sides of cake. Press 1 dowel into centre of 12-inch cake. Mark dowel ¼ inch above top of cake. Remove dowel and cut with serrated knife at marked point. Cut 4 more dowels to same length. Press 4 cut dowels into 12-inch cake, inserting 4 inches inward from cake edges and spacing evenly; press 1 dowel into centre of cake. Refrigerate cake on platter.

Place 9-inch cake on its cardboard on large flat plate or tart-pan bottom. Place plate on cake stand. Using icing spatula, spread 3 cups frosting over top and asides of cake; smooth top. Swirl frosting decoratively on sides of cake. Press 1 dowel into centre of 9-inch cake. Mark dowel ¼ inch above top of cake. Remove dowel and cut at marked point. Cut remaining 3 dowels to same length. Press 4 cut dowels into 9-inch cake, inserting 3 inches inward from cake edges and spacing evenly. Refrigerate 9-inch cake on plate. Place 6-inch cake on its cardboard on another large flat plate or tart-pan bottom. Place plate on cake stand. Using icing spatula, spread 2 cups of frosting over top and sides of cake; smooth top. Swirl frosting decoratively on sides of cake. Refrigerate all cakes until frosting sets - about 2 hours. (Can be made 1 day ahead. Cover cakes and remaining frosting separately with plastic wrap; chill. Bring frosting to room temperature before continuing.)

Using metal spatula as aid, gently place 9-inch cake on its cardboard on top of 12-inch cake, centering carefully on dowels. Gently place 6-inch cake on its cardboard on top of dowels in 9-inch cake. Spoon remaining frosting into pastry bag fitted with medium star tip. Pipe decorative border around base of 12-inch cake and around top-edge of each tier. Arrange berries decoratively inside piped borders atop each tier. (Can be prepared 8 hours ahead; refrigerate.) Let cake stand at room temperature at least 3, and up to 6, hours before serving. Garnish with mint.

To Serve:
Toss berries with sugar in large bowl. Let stand at least 30 minutes and up to 2 hours at room temperature. Remove top and middle cake tiers. Remove dowels from middle cake. Cut top and middle cakes into slices; transfer to plates. Remove dowels from bottom cake. Starting 3-inches inward from edge of bottom cake and cutting through from top to bottom. Cut 6-inch diameter circle in centre of cake. Cut outer portion of cake into slices, then cut inner portion into slices. Spoon berries around cake slices.

Cake pans, cardboard rounds, cake stand and dowels are available at many cake supply shops.