The butter and pan need to be hot when the batter goes in. This allows the pancake to rise and creep up the sides of the pan before the dry ingredients weight it down. If you want puffy pancakes, be sure to follow the steps for melting the butter and heating the pan. If you use a cast iron skillet, heat the butter then, too, for fluffy german pancakes. Using gluten free flour is another contributor to a less puffy batch of german pancake.