Thanks to CSA Member Jennifer Downing for this warming fall meal!
2 pounds butternut or spaghetti squash, cut in ½ and seeds removed
2 tablespoons extra-virgin olive oil, plus more for the pan
1 large onion, finely chopped
Fresh sage, chopped
Kosher salt and freshly ground black pepper
6 cups water
2 cups coarse polenta
4 ounces Gruyere, shredded (about 1 cup)
¼ cup plus 2 tablespoons freshly grated Parmigiano-Reggiano cheese
Preheat the oven to 375°. Place squash halves cut side down on a rimmed baking sheet. Pour water in the pan until just covering the cut edge of the squash and roast for 30 minutes, until tender. Scrape squash from the shell into a bowl and mash coarsely. You should have about 1½ cups. In a skillet, heat 2 tablespoons of olive oil. Add the onion and fresh sage, season with salt and pepper. Cook over medium-low heat, stirring, until caramelized and golden, 25 minutes.
In a saucepan, bring the 6 cups of water to a boil. Whisk in the polenta and 1 teaspoon of salt. Cook over very low heat, stirring frequently, until tender, about 35 minutes. Stir in 1 tablespoon of butter along with the mashed squash, onion, Gruyere and half of the grated Parmesan cheese. Pour the hot polenta into a buttered large casserole dish. Smooth the top slightly without spreading it to the edges; refrigerate until firm, about 3 hours. Rub the surface of the polenta with softened butter and sprinkle with the remaining grated Parmesan cheese. Bake in a 375° oven for 1 hour, until the top and side are lightly browned and crisp. Let stand for 20 minutes before cutting it into wedges and serve topped with serve with sautéed greens