Preheat the oven to 450 degrees F. Melt the butter in a skillet over medium-high heat. Add the corn and 1/2 teaspoon salt and cook until tender, 5 to 6 minutes. Add the scallions and cook until soft, about 1 minute.
Spread the chili in an 8-inch-square baking dish. Top with half of the cheese followed by half of the corn mixture. Lay the polenta rounds on top, then sprinkle with the remaining corn and cheese.
Bake until the casserole is heated through and the top is golden, about 20 minutes. Let stand 5 to 10 minutes before serving.
Slow-Cooker Texas Chili:
Yield:Photograph by Antonis Achilleos
Toss the beef with 1 tablespoon each brown sugar and salt in a large bowl. Heat the vegetable oil in a large skillet over medium-high heat. Cook the beef in batches until browned on all sides, 4 to 5 minutes (do not crowd the pan). Transfer to a 5-to-6-quart slow cooker.
Reduce the heat to medium, add the onion to the skillet and cook until soft, about 5 minutes. Stir in the garlic, chiles, cumin and chili powder and cook 3 minutes. Add 1 1/2 cups water and the tomatoes and simmer, scraping up the browned bits from the bottom, about 3 minutes. Transfer to the slow cooker, cover and cook on low, 7 hours.
Add the remaining 1 tablespoon brown sugar and the hot sauce to the chili. Serve with scallions, cilantro and/or sour cream for topping, and chips, if desired. (Reserve 3 to 4 cups for another use.).