Halloween Cake: Reliable Chocolate Orange Sheet

• **One-pan format:** A 9-by-13-inch cake eliminates layer leveling, filling, and assembly. Its broad surface gives the web pattern room to read across a dessert table, while tidy square portions make serving straightforward for a crowd and reduce the number of plates needed.
• **Built-in decorating plan:** Orange frosting carries color immediately, and a thin black spiral becomes a spiderweb with one toothpick pass. No specialty pan, fondant, or separate decoration batch is required, so the shopping list stays short and finished cake remains easy to slice.

• 1 3/4 cups all-purpose flour (220 g)
• 3/4 cup natural cocoa powder (65 g)
• 1 1/2 teaspoons baking soda (7 g)
• 1 teaspoon baking powder (4 g)
• 1/2 teaspoon salt (3 g)
• 2 eggs (100 g)
• 1 cup buttermilk (240 g)
• 1/2 cup oil (110 g)
• 2 teaspoons vanilla and orange zest (16 g)
• 1/4 cup orange juice, divided (60 g)
• 1 cup butter, softened (227 g)
• 3 1/2 cups powdered sugar (420 g)
• orange and black gel coloring (4 g)

Ingredient notes

• All-purpose flour gives cake enough structure for clean squares and tender crumb. Spoon it into measuring cup, level top, or weigh it; packed flour can make a sheet cake noticeably heavier after baking later.
• Use natural unsweetened cocoa powder, which works with the baking soda for a balanced rise and dark color. Break up any firm lumps before whisking; they can leave dry brown pockets in an otherwise smooth batter.
• Full-fat buttermilk adds tang and keeps the chocolate crumb tender without a separate sour cream purchase. If using powdered substitute, mix according to package directions before adding it rather than stirring powder directly into flour.
• Finely grated orange zest brings brightest citrus note, while juice thins the frosting with a matching flavor. Zest the fruit before juicing, and avoid the white pith; it tastes bitter and can distract from chocolate.
• Gel food coloring gives the black frosting a deeper shade without loosening its piping texture as liquid color may. Begin with a small amount, stir, then add more until spiral clearly contrasts against orange surface.

1. 1Preheat and pan

   Set an oven rack in the center and heat oven to 350°F. Grease a 9-by-13-inch metal pan, line it with parchment leaving two long handles, then grease the parchment. Handles let you lift the cooled cake out for cleaner cuts, though decorating directly in pan also works.

2. 2Whisk dry ingredients

   Whisk flour, cocoa, sugar, baking soda, baking powder, and salt in a large bowl until the cocoa looks evenly dispersed. Rubbing the cocoa lumps between fingers as you whisk is faster than sieving. Make a wide well in the center so wet ingredients combine without overworking the batter.

3. 3Mix batter

   Add eggs, buttermilk, oil, vanilla, orange zest, and orange juice to the well. Whisk from the middle outward until no dry streaks remain, then stop. The batter should be fluid and glossy; continued mixing after that point can make baked crumb less tender and top less level.

   

4. 4Bake and cool

   Pour batter into prepared pan and tap twice to pop large bubbles. Bake until a toothpick near center comes out with a few moist crumbs, 26 to 30 minutes. Cool in pan 20 minutes, then use parchment handles to move cake to a rack.

   

5. 5Frost the cake

   Beat butter until creamy, then beat in powdered sugar, cocoa, salt, vanilla, and orange juice in stages. Spread the orange frosting over a completely cool cake, keeping the layer even at edges. Reserve about one-third cup frosting, tint it black, and transfer it to a small zip-top bag.

6. 6Make web and slice

   Snip a tiny corner from the bag and pipe a spiral, beginning at the center and ending near the edge. Drag a toothpick from center outward at regular intervals, wiping it between strokes. Chill the cake briefly if frosting feels soft, then cut squares with a warm, dry knife.

• Use a light-colored metal pan rather than glass when possible; it gives you a clearer view of edge browning. If your pan is dark, begin checking at 24 minutes because corners may finish ahead of center.
• Cool the cake completely before frosting. A barely warm surface melts buttercream, dulls orange color, and makes web drag rather than hold its crisp lines.
• For a centered web, mark cake's middle with a toothpick before piping. Keep each outward drag in one decisive pass; repeated strokes blur black lines into frosting.
• For clean slices, wipe the knife dry after each cut and use parchment to steady the cake. This small pause keeps orange frosting from smearing across the chocolate crumb.

Set the cake on a black tray or orange-rimmed platter, then place a small stack of napkins beside it before guests arrive. Serve squares at room temperature with vanilla ice cream, whipped cream, or a bowl of clementine segments for a bright option. For a Halloween buffet, label it “chocolate orange web cake” so flavor is clear. Plan one square per person when other desserts are available, or two for a dessert-only spread.