Description
You’ll love this buttery and moist marble loaf cake because it’s beautiful and impressive without any fancy decorating skills required. The chocolate batter is made from the vanilla, so you don’t have to prepare 2 separate cake batters from scratch.
Ingredients
Cake
- 2 cups (250g) all-purpose flour (spooned & leveled)
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 3/4 cup (12 Tbsp; 170g) unsalted butter, softened to room temperature
- 1 and 1/4 cups (250g) granulated sugar
- 3 large eggs, at room temperature
- 1 Tablespoon pure vanilla extract (yes, 1 Tbsp!)
- 1 cup (240g/ml) buttermilk, at room temperature and divided
- 1/2 teaspoon espresso powder
- 1/4 cup (21g) Dutch-process cocoa powder
Chocolate Ganache Topping
- 4-ounce (113g) quality semi-sweet chocolate bar, finely chopped*
- 6 Tablespoons (90g/ml) heavy cream or heavy whipping cream
- optional: fresh raspberries and mint sprigs, for garnish
Instructions
- Preheat the oven to 350°F (177°C) and generously grease a 9×5-inch loaf pan.
- Make the cake batter: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
- Using a handheld or stand mixer fitted with a paddle attachment, beat the butter and sugar together on medium speed until light and fluffy, about 5 minutes. Scrape down the sides and bottom of the bowl with a silicone spatula as needed. Add the eggs and vanilla and beat on high speed for 1 minute. The mixture may look a bit curdled at this point—that’s OK! Scrape down the sides and bottom of the bowl as needed. Pour the flour mixture into the wet ingredients. Turn the mixer to low speed and as the mixer runs, slowly pour in 3/4 cup + 2 Tbsp (210g/ml) of the buttermilk (reserve remaining 2 Tbsp (30g/ml)). Beat on low speed just until combined. Do not over-mix. You may need to whisk it all by hand to make sure there are no large lumps at the bottom of the bowl. The batter will be slightly thick.
- You’ll have about 3–3.5 cups of batter. Transfer a little less than half (just eyeball it, doesn’t need to be perfect) of the batter to another bowl. Warm the reserved 2 Tablespoons of buttermilk in the microwave for 10–15 seconds. Stir the espresso powder into the warm buttermilk until dissolved, then pour it into the bowl that contains slightly less than half of the batter. Sprinkle the cocoa powder over the top, then stir, whisk, or beat on low speed until combined.
- Layer and swirl the batters: Spread a thin layer of the plain vanilla batter in the bottom of your prepared loaf pan. Now you will layer spoonfuls of each batter on top—cover bottom vanilla layer with a few spoonfuls of the chocolate batter, then a few spoonfuls of the vanilla batter, then more chocolate batter, then more vanilla batter, and so on until all of the cake batter is used. Gently shimmy the pan to level out the batters. Using a knife, make rounded horizontal zig-zags from one side of the pan to the other, and then make rounded vertical zig-zags from the top to the bottom.
- Bake for 65–75 minutes, or until a toothpick inserted in the center comes out clean. That time is a guideline—all ovens differ, so keep a close eye on the cake after 55 minutes. If the cake is browning too quickly on top before the center is fully baked, loosely tent a sheet of aluminum foil over top of the pan. (I always tent with foil after 30 minutes.)
- Cool the cake in the pan set on a cooling rack for 30 minutes, then remove the cake from the pan and place it directly on the rack.
- As the cake cools, make the ganache topping: Place the chocolate and cream in a medium heat-safe bowl set over a medium saucepan of simmering water. (Or use a double boiler if you have one.) Do not let the bottom of the bowl touch the water. Stir frequently until chocolate has melted and ganache is smooth. Remove from heat and set aside at room temperature for 20 minutes or until slightly thickened.
- Drizzle or spread topping on cake. Cake is delicious sliced and served slightly warm. The topping sets into a fudge-like consistency after several hours.
- Cover leftovers tightly and store cake (with or without topping) at room temperature for up to 3 days or in the refrigerator for up to 1 week.
Notes
- Freezing Instructions: Topped or plain cake freezes well for up to 3 months. Wrap the cooled cake in a layer of plastic wrap, followed by a layer of aluminum foil. Thaw overnight in the refrigerator, then bring to room temperature or serve cold. See How to Freeze Cakes for more information.
- Special Tools (affiliate links): Dutch-Process Cocoa | 9×5-inch Loaf Pan | Glass Mixing Bowl | Whisk | Electric Mixer (Handheld or Stand) | Cooling Rack | Double Boiler
- Room-Temperature Ingredients: All refrigerated items should be at room temperature so the batter mixes together easily and evenly. Read more about room-temperature ingredients in baking.
- Buttermilk: If you don’t have buttermilk, you can make a DIY buttermilk substitute. Add 2 teaspoons of white vinegar or lemon juice to a liquid measuring cup. Then add enough whole milk to the same measuring cup until it reaches 1 cup. (In a pinch, lower-fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.
- Espresso Powder: Espresso powder will not make the cake taste like coffee. Instead, it deepens the chocolate flavor. You can use the same amount of instant coffee (the powder—not coffee grounds) instead of espresso powder if desired.
- Chocolate: Ganache will only set if the correct chocolate is used. You can use high-quality chocolate chips if needed (I prefer Ghirardelli or Guittard semi-sweet chocolate chips), but I recommend using pure chocolate baking bars, in either semi-sweet or bittersweet. You can find them right next to the chocolate chips in the baking aisle. They are sold in 4-ounce (113g) bars. I like Bakers or Ghirardelli brands.
- Updated in 2025: The recipe above is new and improved. If you prefer to make the original version, expect a denser, flatter loaf. To make that older version, increase the baking powder to 1 and 1/2 teaspoons and skip the baking soda. Reduce the butter to 1/2 cup (8 Tbsp; 113g) and sugar to 1 cup (200g). Use 2 eggs. Skip the buttermilk and replace with 1/4 cup (60g) sour cream and 2/3 cup milk (160ml), plus 2 Tbsp milk for the chocolate batter. Follow the same instructions. The bake time is around 1 hour, same oven temperature.