Peanut-Butter Surprises

INGREDIENTS

• 2 cups all-purpose flour
• 1/2 cup Dutch-process cocoa powder
• 1/2 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/4 pound (1 stick) unsalted butter, room temperature
• 1/2 cup solid vegetable shortening
• 1/2 cup granulated sugar
• 1 1/4 cups firmly packed light-brown sugar
• 2 large eggs
• 1 teaspoon pure vanilla extract
• 1 cup semi-sweet chocolate chips
• 1/2 cup creamy peanut butter