Description

This Spider Cake is a delightfully moist chocolate cake layered with rich chocolate buttercream frosting. Designed to look like a fuzzy spider with bubble tea straw legs and piped eyes, it’s perfect for Halloween or any fun occasion. The cake is baked in 6-inch domed pans with heating cores for even baking and is decorated with a combination of dark chocolate and black gel food coloring to create a striking appearance.

Ingredients

Scale

Moist Chocolate Cake

1 cup all-purpose flour (130g)
1 cup granulated sugar (200g)
1/3 cup dark or Dutch-processed cocoa powder (30g)
1 tsp baking powder (4g)
3/4 tsp baking soda (5g)
1/2 tsp fine salt (3g)
1/2 cup hot water (120g)
1/2 cup buttermilk, room temperature (120g)
1/4 cup vegetable or canola oil (55g)
1 large egg, room temperature (56g)
1 tsp vanilla extract or vanilla bean paste (4g)

Chocolate Buttercream Frosting

1 cup (2 sticks) unsalted butter, room temperature (226g)
1 tsp vanilla extract or vanilla bean paste (4g)
1/4 tsp fine salt (2g)
3 cups powdered sugar (375g)
1/2 cup heavy whipping cream, room temperature (120g)
3/4 cups dark chocolate chips, melted and cooled (135g)
1/2 cup sifted, dark baking cocoa (40g)
Squirt of black gel food coloring

Decoration Tools

8 Black Bubble Tea Straws

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Instructions

Prepare Cake Pans: Preheat oven to 350°F (175°C). Grease two 6-inch domed cake pans and two heating cores with non-stick spray or homemade cake release. Place heating cores in pans for even baking. Set pans on a baking sheet and set aside.
Mix Dry Ingredients: Sift or whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt in a large bowl.
Mix Wet Ingredients: In a separate bowl, whisk hot water, buttermilk, oil, egg, and vanilla extract until fully combined.
Combine Batters: Pour wet mixture into dry ingredients and stir just until incorporated without overmixing.
Bake Cake Layers: Divide batter evenly between pans, filling no more than two-thirds full. Bake 35-40 minutes, or until a toothpick inserted comes out with a few moist crumbs. Cool in pans 10 minutes, then invert onto wire racks to cool completely.
Level Cake Layers: Use a serrated knife to level the tops. Trim 1/2 inch off the dome of one layer for easier stacking. Freeze if making ahead.
Make Buttercream: Beat butter on medium speed 30 seconds until smooth. Add vanilla and salt, mix on low until combined. Gradually add powdered sugar, halfway adding heavy cream to ease mixing. Reserve 1/4 cup white buttercream in a small piping bag with a round tip.
Prepare Chocolate Buttercream: Mix melted dark chocolate, sifted cocoa, and black gel coloring into remaining frosting on low speed until smooth. Reserve 2 tbsp black buttercream in a small piping bag with a small opening. Cover remaining frosting with plastic wrap to prevent crusting.
Prepare Spider Legs: Fold each bubble tea straw halfway and press in a thick book for 20-30 minutes to keep the bend.
Assemble Cake: Place trimmed cake layer on greaseproof board with a dab of chocolate buttercream. Spread even layer of chocolate buttercream on top. Stack second cake layer. Freeze cake for 10 minutes to firm up between layers.
Frost Cake: Coat entire cake with remaining black chocolate buttercream. Smooth with an offset spatula or acetate sheet.
Decorate Eyes: Use white and black buttercream to pipe two eyes on the side of the cake.
Add Legs: Attach 4 bent bubble tea straws on each side of the cake to mimic spider legs. Anchor straws with small strips of clear tape to the cake board. Serve and enjoy!

Notes

Ingredients at room temperature blend more evenly — remember to set out cold items ahead of time.
Measure flour properly by spooning and leveling or use a kitchen scale for accuracy.
Do not overmix batter to ensure tender, fluffy cake layers.
Weigh batter evenly between pans for consistent baking and layer height.
Tap pans on counter before baking to remove air bubbles from batter.
Level cake layers with a serrated knife to enable stable stacking.
Chill cake layers before assembling, to make frosting and stacking easier.
You can prepare cake layers and freeze them ahead for convenience.
Buttercream frosting keeps well refrigerated for up to a month or frozen up to 3 months—stir well after thawing.
A frosted cake stores well refrigerated for a week or frozen for up to a month.

Nutrition

Serving Size: 1 slice (1/12th of cake)
Calories: 420
Sugar: 38g
Sodium: 210mg
Fat: 25g
Saturated Fat: 12g
Unsaturated Fat: 11g
Trans Fat: 0g
Carbohydrates: 47g
Fiber: 3g
Protein: 4g
Cholesterol: 55mg