Enjoy 2 cakes in 1 with this buttery rich marble loaf cake! Baking a cake in a loaf pan means easy prep and minimal decorating without sacrificing any flavor. The chocolate batter is made from the vanilla, so you don’t have to prepare two separate recipes. And don’t forget the 2 ingredient ganache topping!
There’s something so sensational about swirled desserts! I’m no stranger to marbled cakes and my favorites are this wild zebra cake (I used it as the base of my daughter’s “safari” birthday party!) and this giant chocolate marble banana Bundt cake. Have you tried either?
Today we’re relying on our 9×5 inch loaf pan, the magical vehicle that supplies us with banana bread, loaf pan cheesecake, and lemon pound cake.
Here’s Why You Will Love This Cake:
- Tastes rich and moist with prominent vanilla & chocolate flavors.
- It’s just as buttery as pound cake, but with a lighter crumb.
- The 2 cake flavors come from 1 basic batter.
- Assembly is as easy as spooning batter into the pan and swirling with a knife.
- Fuss-free decorating because all of the beauty is on the inside!
If you love homemade cake, but don’t need a towering giant with gobs of sweet frosting, this easy yet impressive dessert is for you. 🙂
Key Ingredients You Need for Marble Loaf Cake:
Adapted from reader-loved chocolate chip loaf cake, this marble loaf cake comes together with basic baking ingredients. You need all of the above plus flour, baking powder, and salt. Let me explain some of the most important:
- Creamed Butter & Sugar: Like most cake recipes, the wet ingredients start with room temperature butter and granulated sugar to create a fluffy creamed base. Unlike most cake recipes, we’ll also add some oil.
- Oil: Oil is a cake’s best friend because it adds exceptional moisture. The test cake without oil was a bit dry. Test cake #2 replaced some butter with vegetable oil and the cake tasted moister and richer. Most notably, however, tasters and I felt the chocolate flavor was more prominent in the loaf made with oil.
- Sour Cream & Whole Milk: Both help create a tender, cake-like crumb.
- Cocoa Powder: You need cocoa powder to make your chocolate batter. Since we use baking powder in this cake recipe, you can use either dutch-process or natural cocoa powder.
- Espresso Powder: As you’ll notice in chocolate cake and chocolate chess pie, espresso powder kicks up chocolate’s flavor. This cake does NOT taste like coffee, rather, it deepens the chocolate.
Success Tip: Use Room Temperature Ingredients
Use Room Temperature Ingredients: All refrigerated items should be at room temperature so the cake batter mixes together easily and evenly. Simply put, cold ingredients won’t properly combine to produce a smooth cake crumb. The batter will have lumps, as pictured below, but if you use cold ingredients, expect a lot of lumps that won’t bake properly.
After you prepare the vanilla batter, transfer some to another bowl and mix in your cocoa powder, more milk, and the espresso powder:
Here’s Exactly How to Swirl The Batters Together
- Spread a thin layer of the plain vanilla batter on the bottom.
- 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.
2 Ingredient Chocolate Ganache Topping
To top the cake, let’s turn to the wonderful dessert concoction known as ganache. Chocolate ganache is typically made with 1:1 semi-sweet chocolate and heavy cream or heavy whipping cream, but for this cake I wanted a thicker-style ganache so I reduced the amount of cream. Since there’s less liquid, it’s best to melt these two ingredients together rather than pour warm cream over the chocolate.
I used milk chocolate in the pictured cake and if you’re using that as well, please see my recipe note because you need even less heavy cream.
Let the ganache thicken for 20-30 minutes and then drape it over your cake. It’s glorious!
Marble loaf cake is built-in beauty with basically zero decoration. We can all appreciate that!
You’ll love this buttery and moist marble loaf cake because it’s easy to make, assemble, and serve without any fancy decoration. The chocolate batter is made from the vanilla, so you don’t have to prepare two separate cake recipes. Review the recipe notes before beginning.
- 2 cups (255g) all-purpose flour (spoon & leveled)
- 1 and 1/2 teaspoons baking powder
- 1/4 teaspoon salt
- 1/2 cup (1 stick; 115g) unsalted butter, softened to room temperature
- 1 cup (200g) granulated sugar
- 1/4 cup (60ml) vegetable oil
- 2 large eggs, at room temperature
- 1/4 cup (60g) full-fat sour cream, at room temperature
- 1 Tablespoon pure vanilla extract (yes, 1 Tbsp!)
- 2/3 cup + 2 Tablespoons (190ml) whole milk, divided and at room temperature
- 3 Tablespoons (16g) unsweetened natural or dutch-process cocoa powder
- optional but recommended: 1/2 teaspoon espresso powder
Thick Ganache Topping
- one 4-ounce (113g) quality semi-sweet chocolate bar, finely chopped (see note)
- 6 Tablespoons (90ml) heavy cream or heavy whipping cream (see note)
- Preheat the oven to 350°F (177°C) and generously grease a 9×5 inch loaf pan.
- Make the cake batter: Whisk the flour, baking powder, and salt together. Set aside.
- Using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter and sugar together on medium-high speed until smooth and creamy, about 2 minutes. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. Add the oil and beat until combined. The mixture will still be quite creamy. Add the eggs and beat on high speed for 1 minute and then beat in the sour cream and vanilla extract. Scrape down the sides and up the bottom of the bowl as needed. The mixture will be lumpy– that’s ok. Pour the dry ingredients into the wet ingredients. Turn the mixer to low speed and as the mixer runs, slowly pour in 2/3 cup (160ml) milk. Beat on low speed just until all of the ingredients are 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 around 3-3.5 cups of batter. Transfer a little less than half (just eyeball it, doesn’t need to be perfect) to another bowl. Stir in the remaining 2 Tablespoons (30ml) milk, the cocoa powder, and espresso powder.
- 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 about 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, loosely tent with aluminum foil as it bakes.
- Cool cake in the pan set on a wire rack for 1 hour before removing from the pan. Note that the cake slightly sinks as it cools and that’s completely normal. Feel free to continue cooling the cake directly on a wire rack or you can top it and slice it while it’s still slightly warm after 1 hour cooling inside the pan.
- 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 20-30 minutes or until slightly thickened.
- Drizzle or spread topping on cake. Topping sets into a fudge-like consistency after several hours.
- Cover leftovers tightly and store cake (with or without topping) at room temperature for 3 days or in the refrigerator for up to 1 week.
- Freezing Instructions: Topped or plain cake freezes well up to 3 months. Thaw overnight in the refrigerator, then bring to room temperature or serve cold.
- Oil: For best taste and texture, use vegetable oil. In a pinch, you can replace with canola oil or olive oil. The cake can taste greasy with melted coconut oil, but if you try it, it’s imperative the other ingredients are room temperature so the coconut oil doesn’t solidify as you mix the batter together.
- Whole Milk & Sour Cream: Feel free to replace the sour cream with low fat plain yogurt. For best results, use whole milk. Lower fat or nondairy milks work in a pinch. I don’t recommend replacing the sour cream and/or milk with buttermilk in this recipe.
- 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.
- Espresso Powder: Espresso powder will not make the cake taste like coffee. Instead, it deepens the chocolate flavor. It’s optional, but for best taste, I highly recommend it. You can use the same amount of instant coffee (the powder) instead of espresso powder if desired.
- Ganache Topping: For the pictured ganache topping, I used 4 ounces of a milk chocolate baking bar from Trader Joes called “Milk Chocolate Pound Plus.” Milk chocolate is softer than semi-sweet and thus produces a thinner ganache. If you use milk chocolate, sometimes sold as “sweet chocolate” or “German’s chocolate” by the brand Bakers, reduce the heavy cream down to 1/4 cup (4 Tbsp; 60ml). If using semi-sweet chocolate, use 6 Tablespoons (90ml) heavy cream as listed above to produce a nice thick ganache.
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