Preheat your oven to 400°F (200°C). Lightly grease an 8-inch baking dish with non-stick cooking spray.
In a medium nonstick skillet, brown the lean ground beef over medium-high heat, breaking it up as it cooks, until it's fully cooked through. Drain any excess fat.
Remove the skillet from the heat and stir in the chopped fresh cilantro, if using.
In the prepared baking dish, combine the rinsed and drained black beans, drained Mexicorn, and light butter spread. Mix them gently.
Evenly spread the cooked ground beef mixture over the bean and corn base in the dish.
Next, spoon your favorite salsa over the beef layer, followed by spreading the light sour cream on top of the salsa.
Finish by sprinkling the shredded low-fat cheddar cheese evenly over the sour cream.
Bake for 20 minutes, or until the casserole is bubbling and the cheese is beautifully melted and lightly golden.
Serve this wholesome casserole warm and enjoy!