Instructions: To make the cake layers: You will need two 6-inch layers, two 8-inch layers, two 10-inch layers, and two 12-inch layers; or eleven and a half batches total (one batch makes one 8-inch layer; 1 1/2 batches makes two 6-inch layers or one 10-inch layer; 2 1/2 batches makes one 12-inch layer.)

Heat oven to 325 degrees. Butter baking pan, line the base with a round of parchment paper, and butter and flour the parchment paper. Cream together the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment until light in color and fluffy, about 5 minutes. Add the vanilla extract. Add the eggs one at a time. Sift together flour, baking powder, and salt 3 times. Add to the egg mixture in 3 additions, alternating with milk, starting and ending with flour.

Pour the batter into prepared pans (filling two-thirds full). Bake 6-inch, 8-inch, and 10-inch for about 35 to 40 minutes, 12-inch for 70 minutes; cakes are done when the tops are golden brown and a tester inserted into the center of cake comes out clean.

To make the meringue buttercream: You will need 4 1/2 batches. In a small saucepan over medium heat, bring sugar and 1/3 cup water to a boil. Boil until syrup reaches soft-ball stage (238 degrees on a candy thermometer).

Meanwhile, beat egg whites on low until foamy. Add cream of tartar; beat on medium-high until stiff but not dry. With mixer running, pour syrup into egg whites in a steady stream, and beat on high speed until completely cool, about 15 to 20 minutes.

Meanwhile, cream butter in a separate bowl to soften. Beat in butter gradually. Add vanilla; beat 2 to 3 minutes, until frosting is smooth and spreadable. If it looks curdled during beating process, continue beating to smooth it out.

To make the sugar syrup: Combine sugar and water in a medium saucepan. Set over high heat; boil until sugar just dissolves. Remove from heat. Let cool.

To make rose petal jam filling: You will need 9 batches. Warm jam in a small saucepan over low heat. Remove from heat and strain through a fine sieve. Let cool to room temperature, about 10 minutes.

To assemble the rose cake: Each cake layer needs a sturdy base. Trace cake pans onto a piece of 3/16-inch foam board, (available at art-supply stores) and cut out the rounds. Once cakes have cooled slightly remove from pans. Do not peel off parchment. When completely cool, place each cake right-side-up on a foam-board round, wrap in plastic, and refrigerate for at least 6 hours; this makes the layers firm and easy to handle. They can also be frozen at this point.

Begin with the biggest tier. Remove from refrigerator. If it didnt bake level - cakes often dont - even it out with a serrated knife. Use a turntable to make it even all around. Place a small dollop of the buttercream in the center of the cake. Put another foam-board round on top of it; invert the cake onto the foam board. Remove the first foam-board base and parchment. The bottom of the cake is now the top; the cake will remain on this foam-board round until it is eaten.

To split the cake, center it on the turn table. Hold a serrated knife against the edge of the cake; rotate the turntable, working the knife through the cake. Brush the cut surface of the bottom half of the cake with the sugar syrup. This syrup will moisten the cake and add a subtle flavor. Pipe the buttercream around the perimeter of the bottom half of the cake. Use a pastry bag fitted with a standard-size coupler. This "dam" will keep the jam filling in place. Fill the bottom layer with jam filling 1/8 of an inch thick; dont use so much that the top layer slips and slides. Carefully replace the top layer with the cut-side down, and brush the top with sugar syrup. Then let set for 2 to 3 minutes.

Ice top with buttercream using an offset spatula to give the tier a "crumb coat." This thin layer of icing will seal the cake. Start from the center and work out, making sure to push the buttercream over the sides of the tier. Smooth the icing. The crumb coat will be covered by more icing later, so it doesnt have to be perfectly smooth at this point. Chill in the refrigerator to set the icing, about 30 minutes to 1 hour, until it doesnt feel sticky when you touch it. Repeat with remaining tiers.

Give the tiers a final coating of buttercream. Use an offset spatula to smooth the top, and a tool called a bench scraper for the sides. Before you ice each tier, wipe off the spatula, dip it in hot water, then wipe it off again; using the warm, clean spatula will make a clean, finished edge. The icing should be smooth and uniform. But perfection is nearly impossible; if you see an air bubble or other small flaw, make that side the back of the cake. Refrigerate the tiers.

Insert a 1/4-inch dowel vertically into the bottom tier of the cake; mark it level with the buttercream. Remove it, and cut 4 dowel pieces to this length. These will be the supports for the next tier. Use the dowels to form a square 1 1/2 inches in from the edge of the tier that will be placed on top (hold an empty cake pan over the finished tier to figure out placement.) Repeat the process on each tier - except the top one - using fewer dowels in different configurations as tiers get smaller. At this point, cakes can be refrigerated overnight.

Assemble the cake on its serving plateau. Dab some buttercream onto the center of the serving plateau and place the bottom tier on it. Place two 10-inch plastic separator plates that have been connected with four 5-inch plastic pillars on top of the bottom tier. Add a dab of buttercream to the top of the 10-inch separator plate and place the 10-inch tier on top of it.

Once all of the tiers are stacked on top of the remaining 8-inch and 6-inch separator plates, insert soaked oasis, cut to fit between each pair of separator plates. Trim the flower stems to about 2 inches. Beginning with the largest roses, insert them randomly in the oasis; using a skewer to aid in making holes. Fill in with a variety of smaller roses and buds.

The final decorative touch is done with pastry bags filled moss green and egg shade yellow buttercream and fitted with a #2 round tip and a #16 star tip. Pipe along the top and bottom edge of the largest tier and the top edge of the remaining tiers.

Serves 100 to 110.

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