Tunnel of Fudge Bundt Cake Recipe

A rich chocolate Bundt cake with a decadent molten fudge center that creates a dramatic tunnel of chocolate when sliced, finished with a glossy ganache.
Difficulty:
Intermediate
Prep Time:
30 mins
Cook Time:
55 mins
Serves:
1 cake (16 slices)
An overhead shot of a beautifully formed Bundt cake on an antique silver cake stand, its distinctive ridged pattern highlighted by a glossy chocolate ganache dripping artfully down the sides. A cross-section slice reveals the cake's signature feature - a dark, moist tunnel of fudge running through the center, creating a striking contrast against the deep chocolate crumb. Soft natural light catches the sheen of the ganache, while scattered walnuts and cocoa nibs decorate the serving plate. A dessert fork rests beside the slice, with a small bite already taken, hinting at the irresistible appeal of this classic chocolate indulgence.

Ingredients

<ul class="ingredients-main-list"><li class="ingredients-single-item">345g unsalted butter, at room temperature</li><li class="ingredients-single-item">400g granulated sugar</li><li class="ingredients-single-item">6 large eggs, at room temperature</li><li class="ingredients-single-item">2 tsp vanilla extract</li><li class="ingredients-single-item">300g all-purpose flour</li><li class="ingredients-single-item">100g unsweetened cocoa powder</li><li class="ingredients-single-item">3/4 tsp salt</li><li class="ingredients-single-item">2 tsp baking powder</li><li class="ingredients-single-item">200g walnuts, finely chopped (or pecans)</li><li class="ingredients-single-item">For the chocolate ganache:</li><li class="ingredients-single-item">170g dark chocolate (70% cocoa), chopped</li><li class="ingredients-single-item">120ml heavy cream</li><li class="ingredients-single-item">2 tbsp unsalted butter</li><li class="ingredients-single-item">1 tbsp golden syrup (or corn syrup)</li><li class="ingredients-single-item">1/2 tsp vanilla extract</li></ul>

Equipment

<ul class="equipment-main-list"><li class="equipment-single-item">25cm (10-inch) Bundt pan</li><li class="equipment-single-item">Stand mixer or electric hand mixer</li><li class="equipment-single-item">Sifter or fine-mesh sieve</li><li class="equipment-single-item">Cooling rack</li></ul>
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Directions

<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Preheat your oven to 165°C (325°F). Thoroughly grease a 25cm (10-inch) Bundt pan with butter, ensuring you get into all the crevices. Dust with cocoa powder, tapping out any excess. This careful preparation ensures your cake will release perfectly after baking.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>In a medium bowl, whisk together the flour, cocoa powder, salt, and baking powder until thoroughly combined. Sift this mixture to remove any lumps - this is crucial for achieving that perfect tender crumb in your finished cake.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>In the bowl of your stand mixer fitted with the paddle attachment (or using a hand mixer), cream the butter on medium speed until smooth and creamy, about 1 minute. Gradually add the sugar and beat on medium-high speed for 5 full minutes until very light and fluffy. This extended creaming process incorporates air into the batter, creating essential structure for your cake.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Add the eggs one at a time, beating well after each addition and scraping down the sides of the bowl as needed. Beat in the vanilla extract. Don't worry if the mixture looks slightly curdled - this is normal and will smooth out when you add the dry ingredients.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>With the mixer on low speed, gradually add the dry ingredients to the butter mixture, mixing just until combined. Be careful not to overmix, which can develop the gluten in the flour and lead to a tough cake. Fold in the chopped walnuts by hand using a rubber spatula.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Spoon the batter into your prepared Bundt pan, smoothing the top with a spatula. The batter will be quite thick - this is exactly what you want for a proper tunnel of fudge cake. Tap the pan gently on the counter a few times to release any large air bubbles.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Bake in the preheated oven for 50-55 minutes. The cake is done when the top feels set and springs back slightly when touched, and a toothpick inserted about 5cm (2 inches) from the edge of the pan comes out with a few moist crumbs. The center will still seem undercooked - this is crucial for creating the fudge tunnel effect! Do not overbake or you'll lose the signature tunnel.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Place the pan on a cooling rack and allow the cake to cool in the pan for exactly 1 hour - no more, no less. This timing is important for proper setting of the fudge tunnel. Then invert the cake onto the rack and let it cool completely, at least 2 more hours, before glazing.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>For the ganache, place the chopped chocolate in a heat-proof bowl. In a small saucepan, heat the cream, butter, and golden syrup until it just begins to simmer at the edges (do not boil). Pour the hot cream mixture over the chocolate and let it sit for 1 minute, then whisk until smooth. Stir in the vanilla extract.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>Let the ganache cool for about 10 minutes until it thickens slightly but is still pourable. Place the cooling rack with your cake over a baking sheet to catch drips, then pour the ganache evenly over the cake, allowing it to drip down the sides naturally. Let the ganache set for at least 30 minutes before serving.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>To serve, slice with a sharp knife, wiping the blade clean between cuts for the most beautiful presentation. Each slice should reveal the namesake tunnel of fudge running through the center. Store any leftover cake covered at room temperature for up to 3 days, or refrigerate for up to 5 days. Bring to room temperature before serving for the best texture and flavor.</li></ol>

Nutrition Facts (per serving)

🍽️ Serving Size: 1 slice
🔥 Calories: 425 calories
🥑 Fat: 24 g
🧈 Saturated Fat: 14 g
🍞 Carbohydrates: 52 g
🍭 Sugar: 38 g
🍗 Protein: 5 g
🫀 Cholesterol: 120 mg
🧂 Sodium: 195 mg

Chef’s Notes

A few helpful details for making this recipe.

Why does my chocolate Bundt cake not have a fudgy centre?

The most common reason is overbaking. The tunnel of fudge forms when the centre remains slightly underbaked. Always test 2 inches from the edge of the pan, not the centre. Also check your oven temperature with a thermometer, as running too hot can overcook the interior before the tunnel sets properly.

Can I substitute the nuts in a Tunnel of Fudge cake?

The nuts are essential for this classic recipe as they contain natural fats that help create the fudgy tunnel texture. While walnuts are traditional, pecans work brilliantly too. For nut allergies, try using the same quantity of chocolate chips, though the tunnel effect may be slightly different.

How do I know when my chocolate Bundt cake is perfectly baked?

Perfect baking is crucial for the fudge tunnel effect. The cake is ready when the top springs back slightly when touched and a toothpick inserted about 5cm from the edge comes out with a few moist crumbs. The centre will still seem undercooked - this creates the signature tunnel!

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