German chocolate cake in a 9×13 pan is the easy, sheet-cake version of the classic: one layer of tender chocolate buttermilk cake, baked at 350°F for 35 to 40 minutes and covered with the traditional cooked coconut-pecan frosting. There is no stacking, no splitting layers and no frosting the sides.
It serves 15 to 18, travels in its pan, and the frosting is spread while the cake is still in the dish, which makes it the best way to take this cake to a potluck or birthday.
Why Bake It in a 9×13 Pan
The layer version uses three 9-inch rounds, and the coconut-pecan frosting only goes between the layers and on top. In a 9×13 pan the same amount of batter bakes as one tall layer (about 1 1/2 inches), and the whole of the frosting sits on top, so every square gets a thick layer of caramel, coconut and pecans. The cake is mild chocolate by design, flavoured with sweet baking chocolate melted in hot water, so the frosting is the star.
Ingredients
Cake
- 4 ounces sweet baking chocolate, chopped
- 1/2 cup boiling water
- 1 cup (2 sticks) unsalted butter, softened
- 2 cups granulated sugar
- 4 large eggs, separated
- 1 teaspoon vanilla extract
- 2 1/4 cups all-purpose flour
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 1 cup buttermilk
Coconut-pecan frosting
- 1 can (12 ounces) evaporated milk
- 1 1/2 cups granulated sugar (or packed light brown sugar for a deeper caramel)
- 3/4 cup (1 1/2 sticks) unsalted butter
- 4 large egg yolks
- 1 1/2 teaspoons vanilla extract
- 2 2/3 cups sweetened flaked coconut (one 7-ounce bag)
- 1 1/2 cups chopped pecans, toasted
Instructions
- Prepare. Heat the oven to 350°F. Grease a 9×13 pan and line the bottom with parchment.
- Melt the chocolate. Stir the chopped chocolate into the boiling water until smooth. Let it cool.
- Cream the butter and sugar. Beat the butter and sugar until light and fluffy, about 3 minutes. Beat in the 4 yolks one at a time, then the vanilla and the cooled chocolate.
- Add dry ingredients and buttermilk. Whisk the flour, baking soda and salt. Add to the batter in three parts, alternating with the buttermilk, mixing on low just until combined.
- Fold in the whites. Whip the 4 egg whites to stiff peaks in a clean bowl and fold them gently into the batter in two additions.
- Bake. Spread in the pan and bake 35 to 40 minutes, until the center springs back and a toothpick comes out clean. Cool completely in the pan on a rack.
- Make the frosting. In a saucepan combine the evaporated milk, sugar, butter and 4 yolks. Cook over medium heat, stirring constantly, until the mixture thickens and turns golden, 10 to 12 minutes; it should reach at least 160°F. Remove from the heat and stir in the vanilla, coconut and pecans. Cool until thick enough to spread, stirring now and then.
- Frost. Spread the frosting over the cooled cake in the pan.
Cook and Prep Times
- Prep: 30 minutes
- Bake: 35 to 40 minutes
- Frosting: 15 minutes plus cooling
- Serves 15 to 18
Doneness and Common Problems
- Sunken center: the cake was underbaked or the whites were deflated. Bake until the center springs back.
- Runny frosting: it was not cooked long enough. It should coat a spoon thickly before the coconut goes in, and it firms as it cools.
- Grainy frosting: the heat was too high. Keep it at a steady simmer and stir the whole time.
Converting From Layer Pans
Any German chocolate recipe written for three 9-inch rounds or two 9-inch rounds fits a 9×13 pan; bake at the same temperature for about 35 to 40 minutes, roughly 10 minutes longer than the layers take. For a thinner sheet in a 10×15 jelly roll pan, bake 20 to 25 minutes. Half the recipe fits a 9×9 pan and bakes in about 30 minutes.
Storage
Because the frosting is made with egg yolks and dairy, cover the cake and refrigerate it after a few hours at room temperature. It keeps for up to 4 days in the fridge; let slices sit out for 20 minutes before serving. You can freeze the frosted cake, tightly wrapped, for up to 2 months.
Frequently Asked Questions
- Is German chocolate cake from Germany? No. It is named after the sweet baking chocolate it uses, not the country.
- Can I use a boxed mix? Yes. A German chocolate cake mix bakes in a 9×13 pan in about 30 to 35 minutes; the homemade frosting still makes the cake.
- Can I skip separating the eggs? Yes, add them whole. The cake will be slightly denser but still good.
Related
- Bread Maker Recipes for a 1.5 Pound Loaf
- Beginner Friendly Bread Machine Recipes
- Pecan Pie Bars in a 9×13 Pan