Chocolate Frosted Cookies

Bahan-bahan (19 porsi)

• 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
• 1 Tablespoon vegetable oil, avocado oil, or olive oil
• 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 and 1/4 cups (156g) all-purpose flour (spooned & leveled)
• 1/2 cup (45g) unsweetened natural cocoa powder
• 1 teaspoon baking soda
• 1/8 teaspoon salt
• 3/4 cup (12 Tbsp; 170g) unsalted butter, softened to room temperature
• 2 cups (240g) confectioners’ sugar
• 6 Tablespoons (30g) unsweetened natural or Dutch-process cocoa powder
• 3 Tablespoons (45ml) heavy cream or milk, slightly warm (see Note)
• 1 teaspoon pure vanilla extract
• pinch of salt
• 1/4 cup (43g) sprinkles (such as these or these)