Chocolate Muffins

Ingredients (12)

• 6 tablespoons unsalted butter
• 4 ounces bittersweet 55% to 72% dark chocolate, roughly chopped, divided
• 2 cups all-purpose flour
• 1/2 cup granulated sugar
• 1/3 cup unsweetened cocoa powder sifted if lumpy
• 1 tablespoon baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 1 cup brewed coffee at room temperature (or swap regular milk; coffee will yield a more intense chocolate flavor)
• 1/3 cup yogurt I used plain, non-fat Greek yogurt, at room temperature
• 1 large egg at room temperature
• 2 teaspoons pure vanilla extract