Bring cast iron skillet to medium heat. Once hot, add enough olive oil to coat the bottom of the pan. Then, add diced onion and bell pepper. Season with salt to taste. Cook for several minutes until the onions are starting to turn translucent, stirring occasionally. Then, add garlic, stir and cook for one more minute until fragrant.
Add ground beef, chili powder, cumin, cayenne (if using) and more salt & pepper. Break apart the beef with your spatula and continue to let cook until browned.
Then add in the tomato sauce, diced tomatoes and kidney beans. Stir. Reduce heat to low, cover the pan and simmer for 15 minutes.
Meanwhile, preheat the oven to 375F. In a large bowl, mix together the cornmeal, GF flour, baking powder and salt. In another large bowl, mix together the greek yogurt, maple syrup, melted butter, and egg. Then add the dry ingredients to the wet ingredients and stir until just incorporated.
Once chili is done simmering, pour the cornbread batter on top of the chili. Gently spread it out and don't worry if it gets a little messy. Transfer to the oven and bake for 25 minutes or until the cornbread is done and slightly golden on top.
Optionally, serve it with a dollop of greek yogurt (or sour cream), shredded cheddar, chopped red onion and chopped cilantro. Enjoy!