To Die For Chocolate Cupcakes

Name: To Die For Chocolate Cupcakes
Cuisine: American
Ingredients: 1⅓ cups (185 g/6.5 oz) all-purpose flour; ½ cup (50 g/1.7 oz) natural unsweetened cocoa powder; ¾ teaspoon baking soda; ¼ teaspoon salt; ½ cup (1 stick/113 g) butter, softened to room temperature; 1 cup (200 g/7 oz) granulated sugar; 2 large eggs; 1 teaspoon pure vanilla extract; ½ cup (120 ml) whole milk; ½ cup (120 ml) hot water; ⅔ cup (1 and ⅓ sticks/150 g) unsalted butter, softened to room temperature; 1⅓ cups (160 g/5.5 oz) powdered sugar, sifted (plus more as necessary); ¼ cup (25 g/1 oz) cocoa powder (Dutch-processed or natural), sifted; ½ teaspoon pure vanilla extract; 115 g/4 oz dark chocolate, melted and slightly cooled; 2 tablespoons (30 ml) heavy cream