This one-bowl vegan chocolate cake is rich, sweet and easy to make. It's perfect for special occasions and for the chocolate lover in your life. This tender cake slices best when it's slightly chilled.
To prepare cake: Preheat oven to 350°F. Lightly coat a 9-by-13-inch baking dish with baking spray.
Combine chocolate chips and hot coffee in a large bowl; let stand for 2 minutes. Stir until the chocolate is melted, about 1 minute. Add oil, almond yogurt, applesauce and vanilla; whisk until smooth.
Add flour, granulated sugar, 3 tablespoons cocoa, baking soda, baking powder and salt; stir until smooth. Spoon the batter into the prepared pan.
Bake until a wooden pick inserted in the center comes out clean, 20 to 25 minutes. Let cool completely in the pan on a wire rack, about 1 hour.
To prepare frosting: Beat vegan butter in a stand mixer fitted with a whisk attachment on medium speed until smooth, about 1 minute. With the mixer running on low speed, gradually add confectioners' sugar and cocoa, stopping to scrape down the sides as necessary. Increase speed to medium-high and add water and vanilla, beating until smooth, about 2 minutes. Spread the frosting on top of the cooled cake. Chill the cake for 1 hour before slicing.
Cover and refrigerate for up to 1 day. Let stand at room temperature for 30 minutes before serving.