Cassata Slab Cake

Preparation

1. Cake

   Step 1

   Place a rack in middle of oven; preheat to 350°. Lightly coat a 13x9" metal baking pan with nonstick vegetable oil spray; line with 2 sheets of parchment, leaving overhang on all sides. (Do not spray parchment.) Beat 4 large eggs, room temperature, 2 cups (400 g) granulated sugar, 1 Tbsp. vanilla extract, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt in the bowl of a stand mixer fitted with the whisk attachment on medium-high speed until pale, fluffy, and nearly tripled in volume, 7–10 minutes (mixture will fall off whisk in an unbroken ribbon when lifted from the bowl). Reduce speed to low and, with the motor running, add 2 tsp. baking powder; mix, scraping down sides of bowl halfway through, until combined, about 1 minute. Add 2 cups (250 g) all-purpose flour and mix until combined, about 1 minute (batter will be very thick); scrape down sides and bottom of bowl.

   Step 2

   Meanwhile, heat 1 cup whole milk and ¾ cup vegetable oil in a small saucepan over medium, stirring occasionally with a heatproof rubber spatula, until steaming (there should be no bubbling), about 4 minutes.

   Step 3

   Pour over batter, scraping saucepan to get every bit. Beat on low speed until batter is smooth, about 2 minutes. Scrape down bowl and fold gently once or twice to ensure batter is well combined (it will be runny). Scrape into prepared pan.

   Step 4

   Bake cake until golden brown and top springs back when gently pressed, 40–45 minutes. Transfer pan to a wire rack and let cake cool. (It will shrink a little bit.) Run an offset spatula around sides of cake to loosen, then invert out onto rack. Peel away parchment and discard. Set pan aside; no need to wash it.

   Do Ahead: Cake can be baked 1 day ahead. Store tightly wrapped at room temperature.

2. Filling

   Step 5

   Mix zest and juice of 1 small orange, zest and juice of 1 medium lemon, 2½ cups whole-milk fresh ricotta, ¾ cup mini semisweet or bittersweet chocolate chips, ¾ cup (83 g) powdered sugar, 2 tsp. vanilla extract, and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in a small bowl until sugar is dissolved. Cover filling and chill until ready to use.

   Do Ahead: Filling can be made 1 day ahead. Keep chilled.

3. Soak and Assembly

   Step 6

   When ready to assemble cake, heat juice of 1 medium lemon, ¾ cup off-dry or sweet Marsala, ½ cup (100 g) granulated sugar, 1 tsp. vanilla extract, and a pinch of kosher salt in a small saucepan over high, stirring occasionally, until sugar is dissolved. Let Marsala soak cool.

   Step 7

   Holding a long serrated knife parallel to cutting board, split cake in half horizontally. Place bottom half, cut side up, in reserved pan. (The cake can break somewhat easily. But don’t fret; you can piece it back together in the pan if needed. You can also place halves on sheets of parchment paper to help you slide them into the pan without breaking.) Brush half of Marsala soak over cake. Dollop filling over; spread into an even layer. Place remaining cake, cut side up, on top. Brush with remaining Marsala soak.

   Step 8

   Wearing kitchen gloves to keep your hands from staining, knead 7 oz. almond paste with a few drops of green food coloring on a surface, dusting with powdered sugar as needed if sticking, until evenly colored and no streaks remain. Place on a sheet of parchment paper dusted with powdered sugar and roll out to about a 14x10" rectangle. Using parchment, invert almond paste onto cake; peel away parchment and discard. Trim and tuck edges to perfectly fit pan; discard excess.

   Step 9

   Whisk remaining 2 cups (220 g) powdered sugar and 2 Tbsp. water in a medium bowl until smooth and very thick. (Add more sugar or water as needed to adjust consistency.) Transfer icing to a pastry bag fitted with a very small straight tip (or use a resealable plastic bag and snip off one corner); pipe a pattern on top of marzipan as desired. Decorate with candied fruit and/or silver dragées as desired.