Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the cooked quinoa, thawed corn, diced tomatoes, black beans, chopped purple onion, and jalapeño (if using). Stir until everything is well mixed.
Pour in the Skinny Ms. enchilada sauce and mix until all the ingredients are evenly coated.
Transfer the mixture into a greased 9x13 baking dish and spread it out evenly. Sprinkle 2 cups of the reduced-fat cheddar cheese on top, reserving the remaining cheese.
Place the baking dish in the preheated oven and bake for 25 minutes.
After 25 minutes, remove the bake from the oven, sprinkle the remaining cheese on top, and return it to the oven for an additional 5-10 minutes.
Once done, let it cool for a few minutes. Top with finely chopped cilantro, sliced black olives, and diced avocado before serving.
