Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).

Halve and seed squash. Place, cut side down, on lightly greased baking sheet. Bake for about one hour or until flesh is easily pierced. (Alternatively, microwave on high, flesh side up, in a covered casserole for 15 minutes or until easily pierced.) Using a fork, gently scrape cooked strands from squash and transfer to a large bowl.

Meanwhile, in a heavy-bottomed pan, heat oil over medium-low heat, add leek and sauté until softening. Add the cole slaw mix and sugar, salt, and pepper. Let cook over low heat for about a half hour. Stir occasionally to avoid any sticking or burning.

Mix with cooked butternut squash strands. Add chopped parsley and serve.