Use butter, stick margarine (with at least 80% oil) or shortening. For best results, do not use whipped, tub, soft, liquid or reduced-fat products. The fat should be softened (at room temperature), meaning it is pliable when touched.Measure ingredients accurately, using the measuring tools and techniques suggested.Before preheating the oven, arrange the oven racks so that the muffins will bake in the center of the oven.Preheat the oven for 10-15 minutes before baking.Standard muffin pans come in different sizes, which affect baking time. The muffin pans we used in this book measure 2-1/2 inches across.Most muffin batters can be baked in jumbo-, standard-, or mini-muffin pans. Just be sure to adjust the baking time in the recipe (more time for jumbo and standard muffins, less time fore mini-muffins). A larger muffin pan will yield fewer muffins than a smaller muffin cup.Fill muffin cups from two-thirds to three-fourths full, wiping off any spills. If your muffin recipe does not fill all the cups in you pan, fill the empty cups with water. The muffins will bake more evenly.Unless directed otherwise, muffins should go directly into the oven as soon as the batter is mixed.Use a kitchen timer. Check for doneness 5-7 minutes before the end of the recommended baking time to avoid overbaking. Muffins are done when a toothpick inserted near the center comes out clean. For muffins with a filling, make sure the toothpick is inserted into the muffin and not the filling.Cool in the pan for 5 minutes, unless the recipe directs otherwise. Muffins are best served warm, fresh from the oven.