- 12 large eggs
- 3/4 cup milk
- 2 tablespoons vanilla
- 1 1/2 teaspoons salt
- 6 cups cake flour (not self-rising)
- 6 sticks unsalted butter (1 1/2 pounds), softened
- 3 cups sugar
- 4 cups lemon syrup
- 2 1/3 cups rose hip, rose fruit, or seedless blackberry jam (about 3 jars, 12 ounces each)
- Cream-cheese frosting
- 8 (1/2-pint) containers blackberries (about 8 cups)
- 1 (12- by 2-inch) cake pan
- 1 (9- by 2-inch) cake pan
- 1 (6- by 2-inch) cake pan
- 2 packages Magi-Cake or homemade foil strips
- 1 (12-inch) serrated knife
- 4 (11-inch) cardboard rounds
- 4 (8-inch) cardboard rounds
- 4 (6-inch) cardboard rounds, trimmed to 5-inch rounds
- 1 medium-size piping bag and 3/16-inch plain tip
- Cake base or large platter
- 5 (8-inch) plastic straws
- Cake-decorating turntable (optional but very helpful)
- Garnish: petals from 3 large organic and nontoxic roses and blackberries (optional)
- Preheat oven to 350°F. Grease cake pans and line bottom of each with a round of wax paper. Grease paper and dust pans with flour, knocking out excess. Wet Magi-Cake strips and fasten around each pan.
- Whisk together eggs, milk, and vanilla. Whisk salt into flour in another bowl. Beat butter (it should be room temperature) with sugar in a 5-qt. standing electric mixer on medium speed until light and fluffy, about 5 minutes. Add flour and egg mixture alternately in 3 batches, ending with egg mixture and beating on low speed just until incorporated.
- Divide batter among pans so each is filled to 1 inch from top. (If you have a wall oven or other small oven, see cooks' notes, below.) Bake in upper and lower thirds of oven, with 12-inch pan on upper rack, 20 minutes. Gently turn pans in place so that part of cake that was toward back of oven now faces front and bake cakes until a tester comes out of each with a few crumbs adhering, 10 to 20 minutes more, depending on cake size. Transfer each cake as done to a rack to cool. Cool cakes slightly (9-inch and 6-inch cakes for 10 minutes; 12-inch cake for 20 minutes) and invert onto racks, peeling off paper. Turn cakes right side up and cool completely.
- Clean pans. Make second batch of batter; bake and cool cakes in same manner.
- Work with 12-inch cakes first. Trim top of each with long serrated knife to make level, then cut cakes horizontally in half. Put each 12-inch layer, cut side up, on an 11-inch cardboard round. Brush cut sides generously with syrup. Stir jam until smooth and spread about 2/3 cup on a 12-inch layer. Invert another 12-inch layer (with cardboard), cut side down, onto jam. Discard top cardboard round and spread about 2 1/2 cups frosting on top. Sprinkle with 1 layer of blackberries to cover frosting. (If berries are 1 inch or larger, halve them lengthwise.) Slide the third 12-inch layer, syrup side up, onto berries, discarding cardboard, and press gently. Spread about 1/2 cup jam on layer and invert the last 12-inch layer (with cardboard), cut side down, onto jam, then discard cardboard.
- Spoon 2 cups frosting onto 12-inch tier and cover cake with a thin coating. (This is called crumb-coating. It tamps down any loose crumbs to keep them out of the top layer of frosting and fills in any crevices.) Chill 12-inch tier while working on remaining tiers.
- Trim and halve 9-inch cakes similarly and put on 8-inch rounds. Brush cut sides generously with syrup. Assemble and crumb-coat 9-inch tier in same manner (use about 1/3 cup jam and 1 1/4 cups frosting between layers; crumb-coat with about 1 1/2 cups frosting). Chill 9-inch tier.
- Repeat procedure to make 6-inch tier (use about 2 1/2 tablespoons jam and about 3/4 cup frosting between layers; crumb-coat with about 3/4 cup frosting) and chill until firm.
- Reserve 2 cups frosting for piping. Place 12-inch tier on cake base (preferably on a cake turntable) and frost. Then frost remaining tiers. Chill frosted tiers (do not stack) at least 4 hours.
- Cut 3 straws in half and insert 1 straw piece in center of 12-inch tier all the way to bottom. Insert remaining 5 straw pieces in a circle about 1 1/2 inches from center straw and trim straws level with top of tier. (Straws support tiers.) Carefully put 9-inch tier (still on cardboard) in center of bottom tier. Cut remaining 2 straws in half and insert into middle tier in similar manner, with 1 straw piece in center and remaining 3 straw pieces in a circle around it. Carefully put 6-inch tier (still on cardboard) on top, in center of middle tier.
- Fill in any gaps between tiers and any imperfections with frosting and transfer the remainder to pastry bag fitted with 3/16-inch tip. Pipe a decorative border around the bottom edge of each tier. Save remaining frosting for touch-ups—just in case.
- Cake should come to room temperature before serving (it may stand at cool room temperature about 6 hours). Garnish cake with roses and serve slices with blackberries.