Southwest Baked Polenta Casserole

Southwest Baked Polenta Casserole is a wholesome, gluten free, vegetarian casserole recipe great for feeding a crowd. Made with simple ingredients like black beans, polenta, green chilies, and plenty of cheese, it’s budget-friendly, easy to make, and great for meal prep! 

Overhead view black bean polenta casserole in a white baking dish

Why You’ll Love This Southwest Baked Polenta Casserole

Around here, we love a good Meatless Monday dish, and this easy polenta casserole recipe is a longtime go-to that we come back to again and again….and again! Seriously. It’s been in our dinner rotation for years, and we still never get tired of it.

After all, not only is it crazy delicious, but it’s also:

  • Made with budget-friendly ingredients.
  • Vegetarian, gluten free, and vegan-friendly.
  • Great for meal prep and feeding a crowd. 
  • Full of vitamins, nutrients, and fiber to keep you nourished. 
Cooked Polenta Casserole in a white pan

What Is Polenta? 

Polenta, also known as stone ground corn, is a paste or dough made from ground cornmeal. An Italian ingredient, it is boiled and served warm similar to oatmeal or grits. Or, it is allowed to cool and solidify into a loaf that is then baked, fried, or grilled.

A hearty ingredient, polenta can be used in both sweet and savory dishes and cooks quickly on the stovetop, in an Instant Pot, slow cooker, or rice cooker. Mild in flavor, it’s super versatile and works great as a binder or base in casseroles, scrambles, soup, and more! We love Bob Redmill’s Organic NON-GMO Polenta and Delallo’s Instant Polenta, but any polenta you find at your local grocery store will work for this polenta casserole. 

How to Cook Polenta

If you don’t have or can’t find pre-cooked or quick-cooking polenta, don’t worry! With a similar cooking process to rice, it’s super easy to whip up. 

  1. Bring 3 ½ – 4 cups of broth to a boil in a large saucepan. 
  2. Working slowly, stir in 1 ¼ cup ground polenta, whisking continuously to prevent it from clumping. 
  3. Reduce the heat, cover the pan, and simmer for 20 minutes or until the liquid is absorbed. 
polenta in pot

Vegetarian, Gluten Free Ingredients You’ll Need

Think vegetarian recipes have to be bland and expensive? Think again! Featuring warm, Southwestern-inspired flavors, this polenta casserole is heavy on flavor yet light on the wallet. 

  • Polenta – To cut down on prep time, we recommend using a quick-cooking polenta like Delallo’s Instant Polenta or pre-cooked polenta. 
  • Butter/Olive Oil – This adds a rich taste to the polenta. For a dairy free option, swap it out for light olive oil instead. 
  • Cheese of Choice – A great source of calcium and plant-based protein, everything tastes better with cheese! We like shredded Cheddar cheese, but you could use Monterey Jack, Parmesan Cheese, Mozzarella Cheese, or anything else you prefer. If needed, use dairy free cheese instead. Just note that the texture of your polenta casserole may change slightly based on what you use. 
  • Flavor Enhancers – Garlic, salt, chili powder, cumin, garlic powder, cayenne pepper, and black pepper combine to create a warm, savory Southwest flavor and add a boost of anti-inflammaory properties
  • TomatoesRo*Tel® Original Diced Tomatoes & Green Chiles and a slight hint of spice and extra moisture to the dish. 
  • Black Beans – These add tons of fiber and plant-based protein to this dish as well as a satisfying texture, making it hearty, filling, and extra delicious. 
  • Garnishes – Technically optional, we love to add cilantro, sliced avocado, sour cream, and sliced jalapeños on top for extra flavor. 

How to Make This Black Bean Polenta Casserole Recipe

  • Prepare the Polenta. In a large pot, cook your polenta according to the package instructions. Just before it is done cooking, whisk in the butter and part of the cheese. 
  • Season. Add the minced garlic cloves, onion, salt, and chili powder to the polenta, and mix to combine. Layer the polenta into a greased baking dish, smoothing it out in an even layer.
Cooked Polenta Casserole in a white casserole dish

Flavor Tip: For a bolder taste, sauté the onion and garlic over medium heat until fragrant before combining it with the polenta. 

  • Prepare the Beans. In a separate bowl, combine the black beans, cumin, garlic powder, cayenne, and black pepper, tossing until the beans are well coated. 
  • Layer remaining Ingredients. Add the black bean mixture on top of the polenta followed by the tomatoes and green chiles. Sprinkle cheese on top. 
black beans over polenta in a white casserole dish
polenta, black beans, and tomatoes in a casserole dish
Pro Tip

Pro-Tip: If your polenta is too runny or moist, parbake it at 350° Fahrenheit for 15 minutes before layering the beans on top. 

  • Bake. Place the polenta casserole in the oven until the edges begin to brown. Then, cover the dish with aluminum foil, and continue to bake until the center of the casserole is completely baked through and the edges are golden brown. *For a crispier texture, broil the casserole at the end of baking until the cheese in browned. 
side view of a black bean polenta casserole
two hands holding a casserole dish of black bean & polenta casserole with a serving mising
  • Serve. Remove the dish from the oven, and let it cool before slicing. Portion the polenta, add your favorite toppings, and enjoy! 

Storage Options

We love to whip up one or two batches of this polenta casserole for easy meal prep to enjoy throughout the week! Once cooled, leftovers can be transferred to an airtight container and stored in the fridge for up to 4 days. 

Or, for a make-ahead option, assemble the casserole, cover it (unbaked), and store it in the freezer for up to 3 months. Then, when you’re ready to bake, let it thaw in the fridge overnight, and bake covered at 350° Fahrenheit. 


More of Our Favorite

Budget-Friendly Vegetarian Comfort Foods

If you love this polenta casserole recipe, you won’t want to miss out on more of our favorite comfort foods, gluten free of course! 

baked polenta with beans in a casserole dish

Southwest Baked Polenta Casserole

  • Author: Lindsay Cotter
  • Total Time: 50 minutes
  • Yield: 5-6 servings
  • Diet: Vegetarian


Southwest black beans polenta casserole is a gluten-free, vegetarian casserole made with black beans, polenta, peppers, cheese, and more. An easy, healthy, freezer friendly dinner recipe!


  • 3 ½ cups cooked polenta (see notes for cooking instructions)
  • 1 Tablespoon butter or light olive oil
  • 68 ounces shredded cheese, divided (see notes for dairy free)
  • 1 teaspoon minced garlic (about 1 clove)
  • cup onion, finely diced *
  • ½ teaspoon kosher salt
  • ½ teaspoon chili powder
  • 1 can (10 ounces) Ro*Tel® Original Diced Tomatoes & Green Chiles, drained (see notes for substitutes)
  • 1 can (15 ounces) black beans, drained and rinsed (22 ½ cups)
  • ½ teaspoon cumin
  • ½ teaspoon garlic powder
  • ¼ teaspoon cayenne
  • ½ teaspoon black pepper
  • Optional Garnishes/Toppings– chopped cilantro, sliced avocado, sour cream, sliced jalapeños


  1. Preheat the oven to 350 F. Coat a 9×13 pan with olive oil or nonstick cooking oil spray and set aside.


Substitutes  – 4 ounces canned green chiles added to a 10 ounce can of regular diced tomatoes (drained) can be substituted for Rotel. Dairy Free Shredded Cheese may be substituted for regular shredded cheese. Texture and taste will vary.

Polenta Cooking Tips – For cooking coarse ground polenta, bring 3 ½ to 4 cups of broth to a boil. Slowly add in 1 ¼ cup polenta, whisking while adding it to the pot so it doesn’t clump. Reduce and cover for 20 minutes until liquid is absorbed.  If using quick cooking polenta like Delallo’s Instant Polenta (cooks in 3 minutes) follow package instructions. You can also buy precooked polenta, crumble into a saucepan over low-medium heat and stir in non dairy milk or broth until heat until combined and creamy. 

Flavor Tip –  Saute onion and garlic until fragrant before mixing with polenta 

Meal Prep – Assemble the casserole (do not bake unless you are par baking the polenta before adding the toppings), cover and store in the freezer for up to 3 months. When ready to bake, remove from the freezer and thaw overnight. Bake covered at 350 F for 30 minutes or until the casserole is cooked through. If desired, uncover and broil until the edges and cheese are browned and crispy. Remove from the oven and let cool for 5 minutes before slicing.

  • Prep Time: 5
  • Cook Time: 45
  • Category: Main
  • Method: Oven
  • Cuisine: mexican-italian- american


  • Serving Size:
  • Calories: 268
  • Sugar: 1.5 g
  • Sodium: 761.5 mg
  • Fat: 14 g
  • Saturated Fat: 6.7 g
  • Carbohydrates: 23.3 g
  • Fiber: 6.3 g
  • Protein: 13.3 g
  • Cholesterol: 35.1 mg

Keywords: polenta casserole, southwest black beans, gluten free dinner, vegetarian casserole

Do you have questions, feedback, or tips about this recipe? Leave a comment below with any questions or feedback you’d like to share!

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