Transfer cookies to wire racks to cool. Meanwhile, fill the second sheet, repeating the resting process and baking while the first batch cools. Makes 40 cookies. So, how come her white potatoes came out looking yellow, Jennifer B. in Coatesville, wants to know. There were no seasonings or other ingredients that would make it that color.
Foods often change color during cooking.
The cause can be a reaction to heat or to contact with some other substance, in the food or in the pan. Being cooked in aluminum, for instance, often adds a gray pallor to white foods such as potatoes or cream sauces. In this case, looking at your recipe for German potato salad, the best guess is that the water the potatoes were cooked in had a high alkaline content. Adding an acidic ingredient such as lemon juice or vinegar, or even baking soda, to the water neutralizes the alkaline content and, in the absence of other colorful ingredients, should keep your potatoes white. In the German potato salad recipe, the dressing contained vinegar, but it wasn't added until the potatoes were already cooked.