Dua Kue Coklat Ganda Besar

Bahan-bahan (2 porsi)

• 3 tablespoons butter, very soft (see photos)
• 5 1/2 tablespoons brown sugar
• 1 egg yolk
• 1/4 teaspoon vanilla
• 4 tablespoons flour (37 grams, see note 1)
• 2 1/2 tablespoons cocoa powder (15 grams, see note 2)
• 1/4 teaspoon baking soda
• 1/8 teaspoon salt
• 3 -4 tablespoons chocolate chips or chunks
• granulated sugar for rolling