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Slice of tunnel of fudge cake with gooey chocolate center, topped with glossy chocolate glaze and nuts on a white plate.

Tunnel of Fudge Cake Recipe with Gooey Chocolate Center – A Classic Crowd-Pleaser

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Prep Time 40 minutes
Cook Time 55 minutes
Cooling Time 1 hour
Total Time 2 hours 35 minutes
Course Cake, Dessert
Cuisine American, Vintage
Servings 12 Slices

Ingredients
  

  • 2 cups (226 g) finely chopped walnuts or pecans (traditional and helps the fudgy texture; toast lightly if you like)
  • 1 3/4 cups (350 g) granulated sugar
  • 1 cup (220 g) packed light brown sugar
  • 1 1/2 cups (339 g) unsalted butter, softened
  • 6 large eggs, at room temperature
  • 2 cups (240 g) all-purpose flour
  • 3/4 cup (64 g) unsweetened cocoa powder (natural cocoa for classic flavor)
  • 1 teaspoon kosher salt
  • 2 teaspoons vanilla extract
  • 1 cup (170 g) mini chocolate chips (optional but boosts the gooey layer)
  • For the pan: softened butter and cocoa powder (or baking spray with flour)
  • For finishing: powdered sugar for dusting or a simple chocolate glaze

Instructions
 

  • Prep the pan and oven. Heat the oven to 350°F (175°C). Generously butter a 12-cup bundt pan, getting into all the crevices. Dust with cocoa powder and tap out the excess. This helps prevent sticking and avoids white flour streaks on a chocolate cake.
  • Toast the nuts (optional but recommended). Spread the chopped nuts on a sheet pan and toast for 6–8 minutes until fragrant. Let them cool completely. This boosts flavor and keeps them crunchy.
  • Beat butter and sugars. In a large bowl, cream the softened butter, granulated sugar, and brown sugar on medium speed for 3–4 minutes until light and fluffy. Scrape the bowl halfway through so everything mixes evenly.
  • Add the eggs, one at a time. Mix in each egg fully before adding the next. When the sixth egg goes in, the batter will look lush and glossy. Stir in the vanilla.
  • Whisk the dry ingredients. In a separate bowl, whisk the flour, cocoa powder, and salt. Break up any cocoa lumps to avoid streaks.
  • Combine wet and dry. Add the dry ingredients to the butter-egg mixture in two additions. Mix on low just until no dry spots remain. Do not overmix or the cake can turn dense.
  • Fold in the nuts and chips. Use a spatula to gently fold in the chopped walnuts or pecans and the mini chocolate chips, if using. This helps form the signature gooey tunnel.
  • Fill the pan. Spoon the batter evenly into the prepared bundt pan and smooth the top. Tap the pan on the counter two or three times to release large air bubbles.
  • Bake. Place on the center rack and bake for 45–55 minutes. The top should be set and cracked, and a tester inserted near the edge should come out clean, while a tester near the center should come out with a few moist crumbs. You want that slight underbake in the core.
  • Cool partially. Transfer to a rack and cool in the pan for 1 hour. This helps the fudgy tunnel thicken so the cake unmolds cleanly.
  • Unmold carefully. Place a serving plate over the pan and invert. Lift the pan off slowly. If it resists, give the pan a few taps and a brief rest.
  • Finish and serve. Dust with powdered sugar or drizzle with a simple glaze (warm 1/2 cup heavy cream, pour over 1 cup chocolate chips, sit 2 minutes, then stir). Slice thick and serve slightly warm for the best gooey center.