In a large bowl, combine flour, baking powder, salt, sugar, and cinnamon. Make a well in the center of the mixture.
In a small bowl combine egg yolks, milk, pumpkin, and butter. Add to the dry ingredients; stirring until the dry ingredients are just moistened.
Beat egg whites at high speed with an electric mixer until stiff peaks form. Fold the egg whites into the pumpkin mixture.
Pour about ¼ cup of batter for each pancake onto a hot, lightly greased griddle. cook until the tops are covered with bubbles and the edges look cooked; flip and cook the other side.