Chocolate and Pumpkin Zebra Cake

Ingredients:
1 cup (2 sticks) unsalted butter, plus more for pan
2 1/3 cups all-purpose flour, plus more for pan
2 teaspoons ground cinnamon
1 1/2 teaspoons kosher salt
1 teaspoon baking powder
1 teaspoon baking soda
1/2 teaspoon ground allspice
1/2 teaspoon ground ginger
1/4 teaspoon ground cloves
1 (15-ounce) can pumpkin purée
1 cup whole milk, room temperature
2 teaspoons vanilla extract
3 cups sugar
4 large eggs, room temperature
Orange food coloring (optional)
1/3 cup unsweetened cocoa powder, sifted
Black gel food coloring (optional)
24 ounces high-quality semisweet chocolate, chopped
3 cups heavy cream
1 tablespoon vanilla extract
Black gel food coloring (optional)
1/2 cup plus 2 tablespoons sugar
2 tablespoons corn syrup
2 (9") round cake pans; a candy thermometer; plastic spider rings (optional)

Instructions:
Position a rack in center of oven; preheat to 350°F. Butter and flour cake pans. Whisk cinnamon, salt, baking powder, baking soda, allspice, ginger, cloves, and remaining 2 1/3 cups flour in a medium bowl. Mix pumpkin purée, milk, and vanilla in another medium bowl.
Cream sugar and remaining 1 cup butter in the bowl of a stand mixer fitted with the paddle attachment on medium speed, occasionally scraping down sides of bowl, until pale and fluffy, 3–4 minutes. Add eggs, one at a time, beating to blend after each addition. Reduce mixer speed to low and beat in dry ingredients in 3 additions, alternating with pumpkin mixture in 2 additions, beginning and ending with dry ingredients.
Transfer 6 cups batter to a large bowl. Whisk in orange food coloring, if using, a few drops at a time until desired color is achieved.
Add cocoa powder to remaining 3 cups batter and beat with stand mixer on medium-low speed until smooth. Add black gel food coloring, if using, a few drops at a time, until desired color is achieved.
Spoon 1 cup pumpkin batter into center of each prepared pan. Spoon 1/2 cup chocolate batter directly on top of pumpkin batter. Repeat 2 times with each batter, spooning batter into centers of pans and occasionally tapping pan firmly on work surface to ensure even distribution. Divide remaining chocolate batter into centers of both pans. The batter will look slightly domed at this point; carefully smooth with an offset spatula, being careful not to disturb the layers too much.
Bake cakes until centers spring back when lightly pressed, 55–60 minutes. Transfer pans to a wire rack and let cakes cool.
Place chocolate in a medium bowl. Heat cream in a small saucepan over medium. Bring to a low simmer, then immediately pour over chocolate. Let sit, undisturbed, 5 minutes. Add vanilla and whisk until smooth. Add black gel food coloring, if using, to achieve a scary black frosting. Let ganache cool at room temperature until thick, about 30 minutes.
Place 2 wooden-handled spoons or spatulas horizontally about 5" apart over a large bowl. Prepare an ice bath in a medium bowl.
Heat sugar, corn syrup, and 2 Tbsp. water in a small saucepan fitted with candy thermometer over medium, stirring, until sugar is dissolved. Bring to a boil over medium heat, without stirring, brushing any sugar crystals down side of pan with a pastry brush dipped in cold water. Cook until thermometer registers 300°F. Immediately dip bottom of pan in ice bath, stirring with a fork. The sugar is ready once it thickens to the consistency of honey but still flows in a steady stream. Remove pan from ice bath and dip fork in hot sugar. Raise fork about 10" above the wooden spatulas and quickly move the fork back and forth, making thin threads of sugar. Repeat, dipping fork back into hot sugar and layering the strands. Form enough strands to create a loose mass resembling a spider web.
Spread 1 Tbsp. ganache in the center of a platter. Place 1 cake layer in the center. Evenly spread 1 1/2 cups ganache on top of cake with an offset spatula, pressing outward toward edges. Carefully place second cake layer, top side down, over, gently pressing down to secure. Evenly spread remaining ganache over top and sides. Chill at least 15 minutes to let ganache set.
When ready to serve, top with spun sugar spider web and plastic spider rings, if using.