Preheat the oven to 400 degrees. Butter muffin pan cups or spray with cooking oil spray.

In a large bowl, combine the flour, sugar, baking powder, baking soda, cinnamon, and salt. In a small bowl, beat the squash, water, vegetable oil, and eggs. Stir the wet ingredients into the flour mixture just until moistened. Stir in 3/4 cup of the nuts. Spoon into muffin cups. Sprinkle tops with remaining nuts. Bake 20 minutes or until tops spring back when touched and a toothpick inserted in the center comes out clean. Cool 5 minutes in the pan. Remove to a wire rack.