1. Mist slow-cooker insert with cooking spray. Warm 2 Tbsp. oil in a large skillet over medium-high heat. Add onion and cook, stirring, until softened, 2 to 3 minutes. Add garlic and chili powder and sauté until fragrant, about 1 minute. Stir in turkey, mixing well and breaking up large clumps of meat. Stir in tomatoes and broth. Add beans, bring to a boil and pour into slow cooker.
2. In a large bowl, combine flour, cornmeal, baking powder and salt. Mix well, then stir in egg, milk, 1/4 cup vegetable oil and cheese. Pour batter over chili in slow cooker and gently spread to cover. Cover slow cooker and cook on low until chili is hot and crust is lightly browned and cooked through, about 5 hours.