Preheat oven to 425 degrees.
Peel and cut up the squash into small cubes and place on a large baking sheet.
In small bowl combine olive oil, pecans, salt and rosemary. Pour the mixture over the butternut squash and use your hands to coat all the pieces.
Place in oven for 30-35 minutes or until tender. Halfway through the cooking time flip the butternut squash.
Remove from oven and sprinkle with extra salt.