Marble Recipe

Prepare and preheat

Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans with vegetable oil or melted butter and lightly dust with 1 tablespoon flour, tapping out excess. Line bottoms with parchment rounds for easy removal.

Dry ingredients

In a medium bowl whisk together 3 cups all-purpose flour, 2 tsp baking powder and 1/2 tsp salt. Set aside.

Cream butter and sugar

In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), beat 1 cup room-temperature unsalted butter and 1 3/4 cups granulated sugar on medium-high speed until light, pale and fluffy, about 3–4 minutes.

Add eggs and vanilla

Add eggs one at a time, beating 20–30 seconds after each addition until incorporated. Scrape bowl as needed. Mix in 2 tsp vanilla extract.

Combine batter

With the mixer on low, add the dry ingredients in three additions alternately with 1 cup whole milk, beginning and ending with the dry ingredients (dry–milk–dry–milk–dry). Mix just until combined. Fold in 1/2 cup sour cream or yogurt by hand until smooth.

Make chocolate portion

In a small bowl, whisk together 3/4 cup unsweetened cocoa powder and 1/2 cup hot water until smooth and no lumps remain. Measure out approximately 2 1/2 to 3 cups of the vanilla batter into a separate bowl (about half to slightly more than half the total batter) and gently fold the cocoa mixture into it until uniformly chocolate. The remaining batter stays vanilla.

Assemble marble batter in pans

Alternate spoonfuls of vanilla and chocolate batter into the prepared pans (start with a large spoonful in the center, then another batter on top) until both pans are about 3/4 full. Use a thin spatula or the handle of a butter knife to gently swirl the batters in an S motion 3–4 times in each pan—do not overmix. Smooth tops slightly.

Bake

Bake in the preheated 350°F (175°C) oven for 28–34 minutes, rotating pans halfway through baking, or until a toothpick inserted into the center comes out with a few moist crumbs but not wet batter. Baking time can vary slightly based on oven and pan material.

Cool

Allow cakes to cool in pans on a wire rack for 10–15 minutes. Run a knife around the edges, invert onto the rack, remove parchment, then invert again so cakes are right side up. Cool completely, about 1 hour, before filling and frosting.

Place 8 oz chopped semisweet chocolate in a heatproof bowl. Heat 3/4 cup heavy cream in a small saucepan until it just begins to simmer (do not boil). Pour the hot cream over the chocolate and let sit 1–2 minutes, then whisk until smooth and glossy. Add 1 tbsp unsalted butter and whisk until incorporated. Let ganache cool at room temperature until thickened but still spreadable, about 30–45 minutes. If it sets too firm, warm briefly over a double boiler and stir to loosen.

Vanilla buttercream

In a mixer bowl fitted with the paddle, beat 1 cup room-temperature unsalted butter on medium speed until creamy, about 1 minute. Reduce speed to low and gradually add 4 cups powdered sugar, then add 2 tsp vanilla extract, 2 tbsp milk or cream and 1/4 tsp salt. Increase speed to medium-high and beat 2–3 minutes until light and fluffy. Adjust consistency with additional milk (1 tsp at a time) if too stiff, or with a little extra powdered sugar if too thin.

Chocolate buttercream

In a clean bowl, beat 1 cup room-temperature unsalted butter until creamy. Add 3 1/2 cups powdered sugar and 3/4 cup sifted unsweetened cocoa powder on low speed to avoid dust. Add 1 tsp vanilla extract, 3 tbsp milk or cream and 1/4 tsp salt. Beat on medium-high until smooth and fluffy, 2–3 minutes. Taste and adjust sweetness or chocolate intensity by adding up to 2 tbsp more cocoa or a tablespoon of powdered sugar as needed.

If cake layers are domed, level the tops with a serrated knife or cake leveler so they stack evenly. Place one layer (cut side up) on a cake board or serving plate.

Spread a thin layer (crumb coat) of vanilla buttercream about 2–3 tbsp on the top of the first layer to act as glue. Pipe or spoon a 1/4–1/3 inch ring of vanilla buttercream about 1/2 inch from the edge to form a collar, then fill the center with 1/3–1/2 cup of the cooled chocolate ganache. Smooth the ganache so it sits flush with the buttercream collar.

Place the second cake layer on top, pressing gently. Apply a thin full crumb coat (a thin layer) of either vanilla or chocolate buttercream around the entire cake to trap crumbs. Refrigerate for 15–20 minutes to set the crumb coat.

Finish icing: Use vanilla buttercream on one half of the cake and chocolate buttercream on the other half to create a contrasting marble/half-and-half effect as in the photo, or cover the whole cake in one flavor and pipe alternating rosettes/stripes of both. Smooth with an offset spatula for a clean transition down the sides, then use a bench scraper to even the sides if desired.

Decoration: Add optional chocolate shavings or sprinkles on top, or pipe decorative borders where vanilla meets chocolate. If you want a marbled piped top, fill two pastry bags—one with vanilla and one with chocolate buttercream—and pipe alternating dabs in concentric circles, then drag a skewer through to create a marbled pattern.

Chill and serve: Chill the finished cake 20–30 minutes to firm the buttercream for cleaner slices. Bring to room temperature 20–30 minutes before serving for best texture. Slice with a sharp knife wiped between cuts.

Yields a moist, tender marble cake with both vanilla and chocolate components. All ingredients in the ingredient list are accounted for in the directions. Adjust sweetness, chocolate intensity, and portion sizes as desired. For a taller cake, bake in three 8-inch pans and adjust bake time to 22–28 minutes.