Double Chocolate and Mint Cookies

INGREDIENTS

• One 5-ounce package chocolate mint thins, such as Andes, each cut into thirds
• 2/3 cup sugar
• 1 cup flour
• 2 tablespoons unsweetened cocoa
• 2 eggs, at room temperature
• 1/4 teaspoon salt
• 2 tablespoons unsalted butter
• 6 ounces semisweet or bittersweet (60-percent) chocolate, chopped
• 1 teaspoon pure vanilla extract
• 1 teaspoon baking powder