Preheat oven to 350 degrees F (175 degrees C). Grease cookie sheets.
In a medium bowl, cream together the butter and sugars until smooth. Beat in the egg and vanilla. Stir in the mashed butternut squash.
In a separate bowl, sift together the flour, baking soda, and cinnamon. Gradually stir into the creamed mixture until blended.
Drop by teaspoonfuls onto the prepared cookie sheet. Bake for 10 to 12 minutes in the preheated oven. Allow cookies to cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Interesting Facts
Butternut squash is a type of winter squash, which is part of the gourd family.
The squash is native to Central and South America, and was first introduced to Europe in the 15th century.
Butternut squash is high in vitamins A and C, as well as dietary fiber.