Roasted Vegetable Chili with Cornbread Biscuits

Name: Roasted Vegetable Chili with Cornbread Biscuits
Ingredients: 1 head cauliflower, cut into small florets; 1 poblano chile pepper, seeded and diced; 4 scallions, roughly chopped, plus more for topping; 3 tablespoons vegetable oil; 1 tablespoon chili powder; 1/2 teaspoon ground cumin; Kosher salt; 3/4 cup cornmeal; 1/2 cup all-purpose flour; 2 teaspoons baking powder; 1 tablespoon packed light brown sugar; 4 tablespoons cold unsalted butter, cubed; 2/3 cup cold buttermilk; 2/3 cup shredded sharp cheddar cheese; 1 15-ounce can black beans, undrained; 1 8-ounce can tomato sauce; 1 1/4 cups frozen fire-roasted corn, thawed; 1 1/2 cups low-sodium vegetable broth