Yield: 14-16 cupcakes
Time: 45 minutes, plus cooling time
1 cup plus 2 tablespoons (140g) all-purpose flour
4oz (113g) dark chocolate, chopped
3/4 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
2 large eggs, at room temperature
1/3 cup (66g) granulated sugar
1/3 cup (66g) packed light brown sugar
¼ cup (60ml) vegetable or canola oil
2 teaspoons pure vanilla extract
1/2 cup (120ml) buttermilk*, at room temperature
3 sticks (12oz, 340g) unsalted butter, at room temperature
4 ounces mascarpone cheese, at room temperature
3 cups (375g) confectioners sugar
½ tsp salt
2 teaspoons vanilla extract
4 ounces (113g) 70% dark chocolate couverture, finely chopped
1/2 cup plus 1 tablespoon (133ml, 4.5oz) heavy cream
2 tablespoons (1oz, 27g) unsalted butter, at room temperature and cut into 4 pieces
2 teaspoons brown rice or corn syrup
*to make a buttermilk substitute, add 1 teaspoon of white vinegar or lemon juice to a liquid measuring cup, then add whole milk until it reaches 1/2 cup. Stir, then let sit for 5 minutes before using.
Preheat the oven to 350°F (177°C). Line muffin pans with cupcake liners. Set aside.
Melt chocolate in microwave or double boiler. Set aside to cool.
Meanwhile, sift together flour, baking powder, baking soda, and salt. Set aside.
In another large bowl, measure in sugars, and then add melted chocolate. Whisk until combined. Add oil and whisk, then eggs and vanilla, mixing until well combined. Pour half of the dry ingredients into the wet ingredients, and then add half of the milk. Gently whisk for a few seconds. Repeat with the remaining wet ingredients and buttermilk. Stir until just combined; do not overmix.
Pour or scoop the batter into the liners. Fill only halfway to avoid spillage over the sides while baking.
Bake for 18-20 minutes or until a toothpick inserted in the center comes out clean. Allow to cool completely before frosting.
Add 2 sticks butter to a skillet set over medium heat. Cook the butter until it until it foams up and then subsides, swirling pan occasionally to keep from burning. Once it smells toasted and brown specks are visible, remove from the heat and transfer to the mixing bowl. Let cool to room temp, about 15 minutes (butter will still be liquid).
Add the remaining ingredients and beat until light and fluffy (5-7 minutes). Decorate cupcakes using a piping tip and pastry bag if desired
Put the chopped chocolate in a medium heatproof bowl.
Bring the cream to a boil and pour half of it over the chocolate. Wait for 30 seconds then gently stir the chocolate and cream together, starting with small circles in the center of the bowl and working your way to the outside. Pour in the rest of the cream and repeat the circular mixing. When the ganache is smooth and shiny, drop in the butter pieces one by one, mixing until each piece is blended before adding the next. Lastly mix in the syrup. Immediately drizzle ganache over frosted cupcakes