Favorite Double Chocolate Chip Cookies

Ingredients

• 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
• 1/2 cup (100g) granulated sugar
• 1/2 cup (100g) packed light or dark brown sugar
• 1 large egg, at room temperature
• 1 teaspoon pure vanilla extract
• 1 cup (125g) all-purpose flour (spooned & leveled)
• 2/3 cup (55g) natural unsweetened cocoa powder
• 1 teaspoon baking soda
• 1/8 teaspoon salt
• 1 Tablespoon (15ml) milk (any kind, dairy or non)
• 1 and 1/4 cups (225g) semi-sweet chocolate chips, plus a few more for optional topping*