For the chocolate cupcakes:
- 5 ounces (142 grams) bittersweet chocolate, finely chopped
- 1/3 cup (28 grams) Dutch-process cocoa
- 1/2 cup boiling water
- 3/4 cup (95 grams) all-purpose flour
- 1/2 cup (100 grams) granulated sugar
- 1/4 cup (50 grams) packed light brown sugar
- 1/2 teaspoon salt
- 1/2 teaspoon baking soda
- 1/2 cup full-fat canned coconut milk, shaken well or whisked until somewhat smooth
- 1/4 cup melted virgin coconut oil
- 2 large eggs plus one egg yolk, at room temperature
- 2 teaspoons white vinegar
- 1 teaspoon vanilla extract
For the coconut buttercream:
- 3 cups (375 grams) powdered sugar, sifted
- 8 ounces (227 grams) unsalted butter, at room temperature
- 1/4 teaspoon fine salt
- 1/2 to 1 teaspoon coconut extract
- 2 tablespoons full-fat canned coconut milk
For the toppings:
- 1 cup (85 grams) shredded sweetened coconut
Make the cupcakes:
In a medium heatproof bowl, add the chocolate and cocoa powder. Pour hot water over mixture. Cover and let stand for 5 minutes. Whisk mixture gently until thick and smooth, then set aside to cool completely.
Meanwhile, preheat the oven to 350°F. Line a standard 12-cup muffin tin with liners.
In a small bowl, whisk together the flour, sugar, brown sugar, salt, and baking soda.
Whisk the coconut milk, coconut oil, eggs, egg yolk, vinegar, and vanilla into the cooled chocolate mixture until smooth. Stir in the flour mixture until smooth, being careful not to overmix.
Using a spring-loaded scoop, divide the batter evenly among prepared muffin cups. Bake until cupcakes are set and firm to the touch, about 17 to 20 minutes.
Let cupcakes cool in pan on a wire rack for 10 minutes before removing from pan to cool completely, about 1 hour. Cupcakes can be stored in an airtight container at room temperature for up to 1 day.
Make the frosting:
In the bowl of a stand mixer fitted with the paddle attachment, mix together the sugar and butter. Mix on low speed until well blended and then increase the speed to medium and beat for another 3 minutes. Add the salt, coconut extract, and coconut milk and beat on medium for 1 minute, adding more cream if needed or more powdered sugar to thicken.
Toast the coconut:
Place the coconut in a medium skillet set over medium heat. Stirring constantly, toast until golden brown. Remove and let cool.
Use an offset spatula to spread the frosting onto each cupcake. Sprinkle with the cooled toasted coconut. Serve or store for 1 day at room temperature or up to 2 days covered in the fridge.