Rose or pink gel food coloring, such as Wilton Rose Petal Pink
Buttercream: (You will make this buttercream twice, so make sure you have enough to double the ingredients)
11/4 cups plus ⅓ cup sugar
½ cup water
8 large egg whites, at room temperature
1 teaspoon cream of tartar
1½ pounds (3 cups; 6 sticks) unsalted butter, at room temperature, cut into pieces
Rose or Pink gel food coloring, such as Wilton Rose Petal Pink
Four 6-oz. containers Driscoll’s Raspberries, divided
8-inch cardboard cake round
Piping bag and large star tip, such as a Wilton 1M tip
Instructions
For the Cake: Position racks in the top third and bottom third of the oven. Preheat oven to 350˚ F. Coat the insides of five 8-inch by 2-inch round cake pans with nonstick spray, line bottoms with parchment rounds, then spray parchment.
Whisk together flour, baking powder and salt in a medium bowl to combine and aerate; set aside. Whisk together the egg whites and milk in a small bowl until thoroughly combined; set aside.
In a large bowl with an electric mixer on medium-high speed, beat butter until creamy, about 2 minutes. Add the sugar gradually and beat until very light and fluffy, about 3 minutes, scraping down the bowl once or twice. Beat in vanilla.
Add the flour mixture in four additions, alternating with the egg white/milk mixture. Begin and end with the flour mixture and beat briefly until smooth. Scrape a generous 2 ¼ cups of batter into one of the prepared pans and level the top with a small offset spatula; this will be your lightest colored layer. Add a tiny bit of food coloring to the remaining batter, blending well until the color is the same throughout. Scrape another generous 2 ¼ cups batter into another pan, leveling that batter as well. Keep adding tiny amounts of coloring to the batter (use photo as inspiration) with each subsequent layer until you have used up all the batter and you have five distinctly colored layers.
Bake for about 25 to 35 minutes or until a toothpick shows a few moist crumbs. The edges will have just begun to come away from the sides of the pan. Cool pans on racks for 10 minutes. Unmold, peel off parchment, and place directly on racks to cool completely. Layers are now ready to fill and frost. Alternatively, double wrap in plastic wrap; store at room temperature if assembling within 24 hours. Layers may be frozen for up to 1 month. Defrost in refrigerator overnight before proceeding.
For the Buttercream: Puree 2 of the raspberry containers in a food processor fitted with a metal blade. Press through a fine meshed strainer; you should have about 1 cup seedless puree. Set aside.
Place 1¼ cups of sugar and water in a small pot. Stir to wet sugar. Bring to a boil over medium-high heat, swirling the pan occasionally. Dip a pastry brush in cold water and wash down sugar crystals from the sides of the pot once or twice. Allow sugar mixture to boil rapidly as you proceed with egg whites.
Meanwhile, place egg whites in a clean, grease-free mixing bowl and whip until frothy on low speed using the wire-whip attachment of a standing mixer. Add cream of tartar and turn the speed up to medium-high. When soft peaks form, add ⅓ cup sugar gradually. Continue whipping until stiff, glossy peaks form.
Bring the sugar/water mixture to a rapid boil and cook until it reaches 248˚ to 250˚ F. When syrup is ready, pour a thin, steady stream directly over meringue. Do not pour any onto the whip or the sides of the bowl. Whip meringue until cool to the touch; this step is very important and may take several minutes. With the machine running, add butter a couple tablespoons at a time. Keep beating until the buttercream is completely thick, spreadable and smooth. Remove 2½ cups of buttercream and set aside for your lightest buttercream roses.
Repeat steps and make the second batch of buttercream. Combine both batches together (they will now fit in the 5-quart stand-mixer bowl), turn machine to low speed and add ½ cup puree. Gradually increase speed and whip until purée is incorporated and buttercream is smooth and pale pink. Remove 5 cups of buttercream and set aside; this will be for the lightest pink roses as well as for the filling and crumb coat. Add an additional ¼ cup puree to the buttercream and beat until smooth, then also add a little food coloring if necessary (about 1/16th teaspoon to start) to make it slightly darker than the last batch. Beat until smooth; remove 2½ cups and set aside. Add more food coloring, beat until smooth, remove 2½ cups and set aside. Tint remaining buttercream in mixer a little darker still. Your amount of food coloring might vary; just make 5 distinct batches.
For Assembly: Have cake layers and buttercream ready to use. Level any of the cake layers if necessary. Place the lightest colored layer on a cardboard round. Spread a thin even layer of palest pink buttercream on top all the way to the edges. Place the lightest pink cake layer on top, repeat with pale pink buttercream, then continue to build cake with each subsequently darker pink cake layer. When the last layer is in place, apply a thin crumb coat of the palest pink buttercream all over the top and sides of the cake. Chill the cake briefly at this point to help the final rosettes adhere. Measure the cake's height and divide by 4. This number will be the height of your roses.
Place tip inside piping bag and fill with white, un-tinted buttercream. Make a rosette of your desired height as follows (making sure it touches and covers the cardboard round): Start in the center, then slowly swirl the frosting around almost 2 times to make a complete rose. Complete an entire band of roses around the cake (see photo for details). Add the lightest pink buttercream to the bag and make your next row of rosettes, making sure they touch the row below and fill in any spaces (you don’t want to see any cake). Add the next darkest buttercream to the bag and repeat with another row of rosettes. Scrape the next darkest pink buttercream into the bag and make your final row, finishing the sides of the cake. Add the darkest buttercream to your bag and cover the top with more roses. Refrigerate cake at least 2 hours to firm up buttercream, or up to 2 days under a large cake dome. Bring to room temperature before serving. Place a mound of fresh berries, using remaining berries, on the center top of the cake right before serving. Set on a display table and wait for oohs and ahhs.
Recipe by Bakepedia at https://www.bakepedia.com/raspberry-rose-ombre-cake-recipe/