Step 1Combine the cream and chopped mint leaves in a saucepan. Bring to a gentle boil, then simmer on low heat for 10 minutes. Remove the pan from the heat and allow the mint leaves to steep 20 minutes. Strain and discard the mint leaves. Clean the saucepan and return the cream to the pan. Heat the cream to a gentle boil.
Step 2Chop the chocolate into pieces no larger than one-fourth inch. Place it in a medium-sized bowl. Immediately pour the hot cream over the chocolate. Tap the bowl on the counter to allow the cream to reach all of the chocolate. Allow the mixture to sit for about 5 minutes.
Step 3Stir with a rubber spatula, beginning from the center of the bowl, until the chocolate and cream are thoroughly combined and no lumps of unmelted chocolate remain. Cover the bowl and refrigerate at least 6 hours, up to four days.
Step 1Position a rack in the lower third of the oven. Heat the oven to 350 degrees. Spray 3 (9-inch) cake pans with pan spray, line them with parchment paper, then spray them again.
Step 2Sift together the flour, baking soda and salt and reserve. In a small bowl, combine the cocoa powder and one-half cup of lukewarm water. Mix thoroughly and set aside to cool. Combine the buttermilk, remaining water and vanilla; reserve.
Step 3In a large bowl, cream together the butter and sugars with an electric mixer until light in color and fluffy, about 6 to 7 minutes, scraping down the sides of the bowl as needed. Add the eggs, one at a time, until fully incorporated. Scrape down the bowl periodically to make sure the ingredients are combined.
Step 4Add the cocoa and water mixture. Beat on medium speed until just combined. Stop the mixer, add one-third of the flour mixture, and beat on low speed only until no flour is visible. Add half the buttermilk mixture, beat on low until just combined. Repeat the process with the remaining flour and buttermilk mixtures, ending with the flour mixture.
Step 5Pour the batter into the prepared pans. Bake until the layers spring back slightly when pressed and a toothpick inserted in the center comes out clean, about 20 to 24 minutes. Cool the cakes in the pans for about 5 minutes before inverting the cakes on a cooling rack top side up and allowing them to cool completely.
Step 6Beat the chilled ganache on medium speed just until it stiffens and holds its shape, like very thick whipped cream. Do not over beat or the ganache will become too thick to spread. (If this happens accidentally, all is not lost. Use a spatula warmed under hot water to spread a too-stiff ganache.)
Step 7Place the bottom cake layer on a piece of heavy cardboard cut out to the same size as the cake. Spread 1 cup of the ganache over the cake, then place the second layer on top and spread 1 cup of the ganache on top. Place the third layer on top, then use the remaining ganache to cover the top and sides of the cake, spreading the ganache as smoothly as possible. Chill the cake at least one hour before glazing it.
Step 1Combine the chopped chocolate, butter, corn syrup and water in the top of a double boiler. Heat over low heat until the chocolate is almost completely melted.
Step 2Remove the mixture from the heat and set it aside to finish melting, stirring once or twice until perfectly smooth. Allow the mixture to cool for about 5 to 10 minutes (or until 88 to 90 degrees) before pouring. The glaze can be made ahead, chilled and re-warmed to 88 to 90 degrees before pouring.
Step 3Place the cake on a rack over a sheet or two of parchment paper. If the glaze has cooled, gently reheat it in the top of a double boiler until it is fluid and shiny. Pour all of the glaze on the center of the cake. Using just 3 or 4 strokes, spread the glaze over the top of the cake so that it runs down the sides. Do not use additional strokes to smooth or spread or the glaze will become dull.
Step 4Decorate the cake with crushed candies, if desired, by carefully placing cookie cutters in the center of the top of the cake and sprinkling the crushed candies within the shape of the cookie cutter. Carefully remove the cutters. Remove the cake from the rack and refrigerate until glaze is set, about 20 minutes. (If cake is made ahead and refrigerated for longer, remove it from the refrigerator one hour before serving.)