For the cupcakes

1. Heat the oven to 350°F. Place cupcake liners into cupcake pans.
2. In a large, heavy saucepan, combine the butter, oil, chopped chocolate, and 1 cup water. Heat over medium heat until melted and fully combined.
3. In a large bowl, whisk the flour, sugar, and cocoa powder. Pour the hot chocolate mixture into the sugar mixture and whisk until combined.
4. Whisk in the eggs, one at a time (making sure to keep whisking – you don’t want the eggs to scramble), then whisk in the buttermilk, vanilla, baking soda, and salt. Fill each cupcake liner about 2/3 full.
5. Bake cupcakes for 17-22 minutes, or until a toothpick comes out clean when inserted into the center. Cool on racks for 10 minutes.

For the frosting

1. In the heatproof bowl of an electric mixer set over a saucepan of simmering water, combine sugar, corn syrup, 1/4 cup water, and egg whites. Cook over medium heat, stirring frequently, until mixture registers 160 degrees on an instant-read thermometer, about 2 minutes.
2. Attach bowl to a mixer fitted with the whisk attachment. Beat mixture on high speed until glossy and voluminous, about 5 minutes. Beat in vanilla. Use immediately. After frosting, use a handheld kitchen torch to lightly toast the top of the frosting if desired.