Preheat the oven to 375F.
In a large bowl, mix the squash and sugar to get rid of all the lumps. Stir or beat in the oil, eggs and vanilla until well-blended and smooth.
Add the flour, cinnamon, baking powder and salt and stir just until combined. (If you like, add a handful of raisins or chocolate chips.) Scoop into about 10 paper-lined muffin tins and bake for 25 minutes, or until golden and springy to the touch. Makes about 10 muffins.