Preheat the oven to 350 degrees . Line a muffin pan with baking liners. In a large bowl, whisk together the flour, granulated sugar, brown sugar, cocoa powder, baking powder and salt. Add the milk, oil, egg and vanilla and stir until blended. Stir in the chocolate chips and pecans.
Fill each muffin cup three-quarters full. Bake until the muffins spring back when touched, about 20 minutes. Transfer to a rack to cool. Insert a plastic doll arm into the center of each muffin.