For many recipes, the kind of potato you use makes a very big difference. There are two important categories of potatoes, baking and boiling. Baking potatoes, or russets (the most famous being Idaho), become soft and fluffy when cooked and are good for any recipe in which you want a lot of starch such as shredded potato pancakes, mashed potatoes, or gnocchi. Boiling potatoes are waxy and remain firm when cooked. Choose them for roasting, and when you are making stew or potato salad. There are also all-purpose potatoes such as Yukon Gold that share some of the characteristics of both baking and boiling potatoes and can be used in any recipe.