Step 1

Place racks in upper and lower thirds of oven; preheat to 350°. Line two 8"-diameter and two 9"-diameter cake pans with parchment paper rounds (do not grease; chiffon cakes rise higher in an ungreased pan). Beat 8 large egg whites, room temperature, 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt, 1 tsp. cream of tartar, and 1 cup (packed; 200 g) brown sugar in the bowl of a stand mixer fitted with the whisk attachment on medium-low speed until egg whites are broken up, about 30 seconds. Increase speed to medium-high; beat until meringue is glossy and holds medium peaks, 8–10 minutes.

Step 2

Whisk 8 large egg yolks, room temperature, and remaining 1 cup (packed; 200 g) brown sugar by hand (or with a hand mixer) in a large bowl until pale and well combined, about 2 minutes (mixture will seem stiff). Whisk in ⅔ cup vegetable oil, 2 tsp. vanilla bean paste or vanilla extract, and ⅔ cup room-temperature water. Sift 2 cups (250 g) cake flour and 1 tsp. baking powder over and whisk vigorously to combine.

Step 3

Add one fourth of meringue to egg yolk mixture; mix to incorporate. Add remaining meringue in 3 additions, gently folding with a rubber spatula after each addition until only a few streaks remain.

Step 4

Divide batter among prepared pans to come ¾" up the sides (300 g in each 8" pan; 350 g in each 9" pan) and gently smooth surface. Run a chopstick through batter a few times to break up any large air bubbles. Bake cakes 15 minutes. Reduce oven temperature to 325° and continue baking until cakes are golden brown and tops spring back when gently pressed, 15–18 minutes more (smaller cakes may be done first). Invert pans onto 2 wire racks and let cakes cool in pans, about 1 hour. (Cooling cakes upside down reduces shrinkage.)

Step 5

Turn pans over. Run an offset spatula around sides of cakes to loosen, then invert onto wire racks; peel away parchment.

Step 6

Working in batches if needed, pulse 1 cup (46 g) freeze-dried strawberries, 1 cup (200 g) granulated sugar, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, and 1 tsp. finely grated lemon zest in a food processor until finely ground. Add 2 oz. cream cheese, room temperature, 4 cups chilled heavy cream, and 2 tsp. vanilla bean paste or vanilla extract and process, scraping down sides halfway through, until mixture is thick and mousse-like, about 2 minutes. Transfer to a medium bowl; cover and chill. Rinse out and dry food processor.Do ahead: Strawberry cream can be made 1 day ahead. Keep chilled.

Step 7

Pulse 1¼ cups chilled heavy cream, 1 cup creamy peanut butter, ⅓ cup (67 g) granulated sugar, 1 tsp. vanilla bean paste or vanilla extract, and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in food processor, scraping down sides as needed, until mixture is thick and creamy, about 1 minute (it’s okay if some sugar remains undissolved). Transfer to a small bowl.

Step 8

Line a large bowl (10"–11"-diameter at top; 4"–5"-diameter at base) with plastic wrap, leaving a 6" overhang. Using a 4"–5"-diameter plate or bowl as a template (size should match base of large bowl), cut out a round from one 8" cake layer (scraps are baker’s treat). Using a 6"-diameter plate or bowl as a template, cut out a round from one 9" cake layer. Transfer 2½ cups strawberry cream to a piping bag (no tip needed) or a plastic bag with ¼" cut diagonally from 1 corner.

Step 9

Place smallest cake layer in large bowl (it should sit flush against base) and spread 2 Tbsp. strawberry jam evenly over top. Spoon about ¼ cup (65 g) peanut butter filling on top of jam and spread evenly with an offset spatula. Scatter 2 Tbsp. coarsely chopped honey-roasted peanuts over filling. Pipe strawberry cream to fill in gap between cake and bowl. Stack 6" cake layer on top; spread with 3 Tbsp. strawberry jam, then with about ½ cup (130 g) peanut butter filling. Pipe strawberry cream around cake to fill gaps. Scatter 3 Tbsp. coarsely chopped honey-roasted peanuts over filling. Stack 8" cake layer on top and spread with remaining 3 Tbsp. strawberry jam, then with about 1 cup (260 g) peanut butter filling. Pipe strawberry cream around cake to fill gaps. Scatter remaining 3 Tbsp. coarsely chopped honey-roasted peanuts over filling. Stack 9" cake layer on top, pressing down firmly to adhere. Bring plastic overhang up and over to cover. Chill until cream is set, about 1 hour.

Step 10

Peel back plastic from surface of cake. Place a cake stand or large plate upside down over bowl and invert; unmold cake and carefully remove plastic. Set aside ½ cup strawberry cream for decorating; spread remaining strawberry cream in an even layer over top and sides of cake with offset spatula, mounding cream on top slightly to create a more pronounced dome shape. (For the cleanest dome shape, use a 9x4" strip of acetate—a flexible plastic sheet—to smooth strawberry cream: Grip ends of acetate and pull gently up slope of dome and down the other side, rotating cake as you go.) Chill cake, uncovered, at least 1 hour and up to 8 hours.

Step 11

Just before serving, transfer reserved strawberry cream to a piping bag fitted with a St. Honore or other petal tip or to a plastic bag with ¼" cut diagonally from 1 corner. Pipe squiggles over cake. Press food-safe flowers and leaves and freeze-dried strawberries onto surface of cake as desired.Do ahead: Cake (without decorations) can be assembled 1 day ahead. Cover loosely and keep chilled.