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chocolate sheet cake in silver pan
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Minnesota Sheet Cake

This thin and moist chocolate cake is fit for a crowd! Extra cocoa powder and a hot cup of coffee in the cake base give this cake excellent flavor, but then, even more chocolate (in the form of ganache) poured over the warm cake truly made this a winner.
Course cake
Cuisine American
Diet Low Salt, Vegetarian
Keyword chocolate, cocoa powder, coffee, walnuts
Servings 20 servings

Ingredients

Cake

  • 1 cup [200 g] granulated sugar
  • 1 cup [200 g] brown sugar
  • 8 tablespoons [1 stick or 113 g] unsalted butter, melted
  • 3/4 cup [75 g] Dutch-process cocoa powder
  • 1/2 cup [112 g] vegetable oil or canola oil
  • 1/2 cup [120 g] crème fraîche or sour cream, at room temperature
  • 3 large eggs, at room temperature
  • 2 large egg yolks, at room temperature
  • 2 teaspoons pure vanilla extract
  • 1 teaspoon fine salt
  • 1 teaspoon baking soda
  • 1/2 teaspoon baking powder
  • 2 cups [284 g] all-purpose flour
  • 3/4 cup [180 g] strong, freshly brewed coffee, hot

Ganache

  • 1 pound [455 g] bittersweet chocolate, finely chopped
  • 2 cups [480 g] heavy cream

Candied Nuts

  • 1/2 cup [100 g] granulated sugar
  • 1/4 cup [60 g] water
  • 1/4 teaspoon salt
  • 2 cups [280 g] black walnuts or pecans,

Instructions

For the cake

  • Position an oven rack in the middle of the oven and preheat the oven to 350F [180C]. Grease an 18 by 13 by 1 in [46 by 33 by 2.5 cm] half sheet pan.
  • In a large bowl, whisk together the granulated and brown sugars, melted butter, cocoa powder, oil, crème fraîche, eggs, egg yolks, vanilla, salt, baking soda, and baking powder. Add the flour and use a spatula to combine it into the batter. Slowly pour the hot coffee into the batter and mix until just combined. Pour the batter into the prepared pan and use an offset spatula to smooth the top.
  • Bake for 18 to 24 minutes, until a wooden skewer or toothpick inserted into the center comes out with the tiniest bit of crumb. Transfer the pan to a wire rack and let cool for 5 minutes.

For the ganache

  • While the cake is cooling, make the ganache: Place the chopped chocolate in a medium heatproof bowl. Heat the heavy cream in a small saucepan until it is simmering and just about to boil. Pour the cream over the chocolate, cover the bowl with plastic wrap, and let sit for 5 minutes.
  • Remove the plastic and whisk until completely smooth. Use immediately.

For the candied nuts

  • Line a sheet pan with parchment paper.
  • In a large skillet over medium heat, carefully stir together the sugar, water, and salt. Cook over medium heat until the sugar begins to melt and starts to turn golden. Shake the pan and add the nuts, stirring to completely coat. Remove from the heat and pour the nuts onto the prepared pan, then cool completely before chopping.

To Assemble

  • Starting in the center of the cake, carefully pour the ganache over the warm cake, using an offset spatula to smooth it over the top. Sprinkle the ganache with the candied nuts. Let sit until the cake is cooled to room temperature. Chill, if desired, then cut into squares and serve. The cake can be stored in the refrigerator, covered, for up to 3 days.

Notes

  • Throughout my recipes posted on this website, 1 cup of flour equals 142g. Please note that 1 cup of flour can range anywhere from 120g to 142g, depending on the baker or website. I found that after weighting many cups of flour and averaging the total, mine always ended up around this number. If I am posting a recipe from another cookbook, I will use whatever gram measure of flour used in that book, which is why you may see a few posts with a different cup measurement. Different brands of flour have varying levels of protein, ranging from low to high, which can result in very different outcomes when baking. I’ve found Gold Medal all-purpose unbleached flour to be the best option for many of my recipes; I use it in all the baked goods that don’t use yeast.