Eggless Chocolate Cupcakes

Name: Eggless Chocolate Cupcakes
Prep time: 20 min
Total time: 20 min
Cuisine: American
Ingredients: 192 grams all purpose flour (1 1/2 cups); 200 grams granulated sugar (1 cup); 30 grams unsweetened cocoa powder (1/4 cup); 2 teaspoons instant espresso powder; 1 teaspoon baking soda; 1/4 teaspoon fine sea salt; 240 milliliters boiling water (1 cup); 70 milliliters vegetable oil (1/3 cup); 15 milliliters white vinegar (1 tablespoon); 1 teaspoon vanilla extract; 170 grams unsalted butter, softened (12 tablespoons; 1 1/2 sticks); 405 grams confectioner’s sugar (3 cups); 30 grams cocoa powder (1/4 cup); 30-45 milliliters whole milk, plus more to adjust consistency (2-3 tablespoons); 1/8 teaspoon fine sea salt