Chocolate Swirl Meringue Cookies

Bahan-bahan (3 porsi)

• 2 ounces (55g) semi-sweet chocolate, finely chopped
• 3 large egg whites (120g), at room temperature (see note)*
• 1/4 teaspoon cream of tartar
• 1/8 teaspoon salt
• 2/3 cup (130g) granulated sugar
• optional: sprinkles