Seven layer Icebox Cake

Chocolate curls Additional unsweetened Dutch process cocoa powder Candied violets Ready a serving board or platter. The finished cake will be about 9 inches long by 4 inches wide by 2-1/2 inches tall. Remember you'll have to slice the cake on the board or platter; I prefer to use something rectangular and without sides. I also line my board with aluminum foil, but this is optional. Have ready the Petit Beurre cookies. In a one-cup liquid measuring cup, dissolve the coffee in a small amount of hot water. Add cold water to the 1/2 cup mark. Add rum; pour into small dish (with sides). The dish must be able to accomodate one Petit Beurre, and the coffee-rum mixture in the dish must be deep enough so that the Petit Beurre can be completely submerged in it. Cover tightly and set aside at room temperature. In large bowl of electric mixer fitted with whisk beater, beat softened butter at medium speed until creamy. Gradually add sifted confectioners' sugar, cocoa powder, and salt. Be sure to scrape bowl and beater(s) with large rubber spatula often. When all dry ingredients are added, increase speedto high; beat until fluffy. Add vanilla at a low speed. If necessary to achieve good spreading consistency, add a small amount of the coffee-rum mixture, a bit at a time. One at a time, dip each Petit Beurre in the coffee-rum mixture, holding it under the liquid for a couple of seconds. Do not submerge the Petit Beurres for so long that they become soggy. Each layer of the cake will consist of eight dipped cookies in a four-by-two pattern; the cookies should be touching one another. As you put each dipped cookie into place, you'll be able to see the cookies absorbing the coffee-rum. When you have formed the first cookie layer of eight, frost the top. I use as much frosting as I can pile onto a tablespoon (not a measuring tablespoon). An offset spatula is a big help for this. Spread the frosting right to the edges of the cookie layer. Don't use too much frosting, though, or you won't have enough to go around. Repeat the dipping, layering, and frosting of the cookies. As you put a dipped cookie on top of a frosted layer, press it in slightly. If necessary, straighten the sides of the cake with your hands. When you've built up seven cookie layers, frost the top and sides of the cake with the remaining frosting. If desired, gently pat chocolate curls onto the top and long sides of the finished cake. Chill at least 6 hours (or overnight), covering tightly when frosting is set. To serve, remove cake from refrigerator. Allow to stand at room temperature, still covered, for about 20 minutes. To slice, use a large, sharp, heavy knife; press it down firmly through the cake. I like to make slices about 1/2 inch thick, but you can make them thinner. Transfer each slice to a serving plate. If desired, dust a little unsweetened Dutch process cocoa powder around the edges of the plate for decoration, and/or top each slice with a candied violet or two. Store any leftovers in refrigerator, tightly covered, for up to 5 days. 16 to 18 servings