Black-bottom Cupcakes

Ingredients

• 8 ounces cream cheese, regular or reduced fat, at room temperature
• 1/3 cup granulated sugar
• 1 large egg, at room temperature
• 2 ounces bittersweet or semisweet chocolate, coarsely chopped
• 1 1/2 cups all-purpose flour
• 1 cup firmly packed light brown sugar
• 5 tablespoons natural unsweetened cocoa powder (not dutch-process)
• 1 teaspoon baking soda
• 1/4 teaspoon salt
• 1 cup water
• 1/3 cup unflavored vegetable oil
• 1 tablespoon white or cider vinegar
• 1 teaspoon vanilla extract