2 1/4 cups sugar
1 1/4 teaspoons salt
2 1/2 teaspoons baking soda
1 egg yolk
1 1/4 cups + 1 tablespoon buttermilk
1 cup + 2 tablespoons canola oil
1 1/2 teaspoons vanilla extract
2 1/2 cups + 2 tablespoons all-purpose flour, sifted
3 ounces unsweetened chocolate, roughly chopped
6 tablespoons unsalted butter
1 1/2 cups powdered sugar
1/4 cup sour cream
1/8 cup brewed coffee, at room temperature
- Preheat oven to 350 degrees F. Spray a 10-inch Bundt pan with nonstick cooking spray and sprinkle the inside with flour.
- Combine brewed coffee and cocoa powder in a small saucepan and bring to a boil, whisking frequently. Remove from heat and let cool to room temperature, about 30 minutes.
- When the coffee mixture is nearly cool, combine sugar, salt, baking soda, eggs and egg yolk in the bowl of a standing mixer fitted with the whisk attachment. Mix on low until evenly combined, about 1 minute.
- Add buttermilk, oil and vanilla extract and mix on low for 1 minute. Add flour and mix on medium for 2 minutes. Add cooled coffee mixture and mix on medium for 3 minutes.
- Pour into bundt pan and bake until a toothpick inserted near the middle comes out clean, about 60 minutes.
- Cool cake in pan for 5-10 minutes before inverting onto a plate and letting cool completely.
- Make the glaze: melt chopped chocolate and butter in the top half of a double boiler set over hot water. Whisk until smooth and melted. Remove from heat.
- Sift in half the powdered sugar. Add sour cream and whisk to combine. Sift in the remaining powdered sugar and whisk until smooth.
- Add coffee and whisk to create a glossy glaze. Thin with a little hot water if glaze is too thick. Pour glaze over cake, letting it drip down the sides and middle.