I like to use a variety of apples, so the sauce has a mix of tart, sweet, firm and softer apples. It makes the apple sauce taste better and have a more interesting texture. I just cook the apple, but don't necessarily puree them. That is up to you and your preference. The other decision to make is whether or not you want to peel the apples or leave the skins on. If you leave the skins on, then you'll want to puree the applesauce, since they can get "stringy" and I don't care for that texture.