2 ounces bittersweet chocolate, chopped
1/4 cup heavy cream
1 tablespoon confectioners’ sugar
3 ounces bittersweet chocolate, chopped
1/3 cup (1 ounce) Dutch-processed cocoa powder
3/4 cup hot water
3/4 cup (4 1/8 ounces) bread flour
3/4 cup (5 1/4 ounces) granulated sugar
1/2 teaspoon salt
1/2 teaspoon baking soda
6 tablespoons vegetable (or canola) oil
2 large eggs
2 teaspoons white vinegar
1 teaspoon vanilla extract
1/3 cup (2 1/3 ounces) granulated sugar
2 large egg whites
12 tablespoons (1 1/2 sticks) unsalted butter, softened and cubed
6 ounces bittersweet chocolate, melted and cooled
1/2 teaspoon vanilla extract
Preheat the oven to 350°F. Line a standard 12-cup muffin pan with paper liners. Set aside.
Place the chocolate, cream, and confectioners’ sugar in a medium, microwave-safe bowl. Microwave until the mixture is warm to the touch, 20-30 seconds. Whisk the mixture until smooth, then refrigerate until just chilled, no longer than 30 minutes.
Meanwhile, place the chocolate and cocoa powder in a large bowl. Pour the hot water over the mixture and whisk until smooth. Refrigerate until completely cool, about 20 minutes. Whisk the flour, sugar, salt, and baking soda together in a medium bowl and set aside.
Whisk the oil, eggs, vinegar, and vanilla into the cooled chocolate-cocoa mixture until smooth. Add the flour mixture and whisk until smooth.
Divide the batter evenly between the cupcake tins. Place one heaping teaspoon of the ganache filling on top of each cupcake. Bake until the cupcakes are just set and firm to the touch, 17-19 minutes. Cool the cupcakes in the pan on a wire rack until cool enough to handle, about 10 minutes, then carefully remove each cupcake from the pan and place on a wire rack. Cool to room temperature before frosting.
In the bowl of a stand mixer, combine the sugar, egg whites, and salt, then place the bowl over a pan of simmering water. Heat the mixture, whisking gently but constantly, until slightly thickened and foamy and it registers 150 degrees on an instant-read thermometer, 2-3 minutes.
Using the whisk attachment, beat the mixture on medium speed in a stand mixer until slightly cooled, 1-2 minutes. Add the butter, 1 piece at a time, until smooth and creamy (The mixture may look curdled, but it will come together after adding the chocolate and vanilla). Once all the butter is added, add the cooled melted chocolate and the vanilla and mix until combined. Increase the speed to medium-high and beat until light, fluffy, and thoroughly combined, 30 seconds, scraping the sides of the bowl with a rubber spatula as necessary.
** Note: The frosting can be made in advance and refrigerated until ready for use. When ready to frost, place the frosting in a microwave-safe bowl and microwave briefly until just slightly softened, 5-10 seconds. Once warmed, stir until creamy.