Preheat your oven to 375°F (190°C) and grease a 9 by 13 inch baking dish.
Heat the 1 tablespoon olive oil in a large skillet over medium high heat. Add the 1 pound ground beef and cook, breaking it up, until browned. Add the diced onion and cook for 3 minutes, then stir in the 3 cloves minced garlic for 1 minute more.
Stir in the 1 tablespoon chili powder, 1 teaspoon cumin, 1 teaspoon smoked paprika, ½ teaspoon salt, and ½ teaspoon black pepper, and cook for 1 minute, until fragrant.
In the greased baking dish, combine the beef mixture, 1½ cups uncooked rice, the can of diced tomatoes, kidney beans, black beans, 1 cup corn, 2½ cups beef broth, and ½ cup salsa. Stir until evenly mixed.
Stir in 1 cup of the cheddar, then spread the mixture into an even layer and press down gently so the rice is submerged in the liquid. This is what lets it cook evenly.
Cover the dish tightly with aluminum foil, crimping it around the edges. A tight seal traps the steam that cooks the rice, and a loose cover is the main reason these bakes come out crunchy. Bake for 35 minutes.
Remove the foil and give everything a gentle stir, checking that the rice is tender. Scatter the remaining 2 cups cheddar over the top and return to the oven uncovered for 8 to 10 minutes, until the cheese is melted and bubbly.
Let the bake rest for 5 minutes, then top with the sliced green onions and ¼ cup cilantro before serving.