Roasted Butternut Squash with Rosemary and Balsamic Vinegar

(4-6 servings, adapted from a recipe by Lynn Rosetto Casper found on Foodieview.)
2 lbs. butternut squash cubes (about 6 cups)
2 T extra virgin olive oil1 T + 1 tsp. best quality balsamic vinegar
1 tsp. very finely chopped fresh or frozen rosemary, or slightly less dried rosemary (be sure it's especially finely chopped if you use dried rosemary)
sea salt to tastefresh ground black pepper to taste

Preheat oven to 400 F. Toss squash cubes with olive oil, 1 T balsamic vinegar, and rosemary. Put on cookie sheet or dish large enough to hold it in a single layer. Roast until squash is very soft and starting to get slightly caramelized, about 40 minutes.Remove from oven, put squash in bowl, and toss with additional 1 tsp. balsamic vinegar, sea salt, and pepper. You can mash slightly, I kept mine rather chunky. Serve hot. This is also excellent made ahead and reheated. For a meal where there are lots of demands on the oven, it could be cooked early in the day and kept warm in a crockpot while other things bake.