Set a steamer basket in a saucepan filled with 1 inch water. Cover; bring to a boil. Add pumpkin. Cover; cook until very tender, about 15 minutes. Puree in a food processor until smooth.
Unlike deeply ridged, hard squash such as acorn, smooth sugar pumpkins are easy to prep. Cut off the top and bottom ends, then use a vegetable peeler to remove the skin. For tougher skin, make a few more passes with a vegetable peeler.