Southwestern Casserole (Vegetarian)

This Southwestern Casserole is an amazing vegetarian comfort food. It’s layered with grilled zucchini, mushrooms, black beans, caramelized onions, and Latin flavors throughout.

Zucchini is one of the most versatile squashes, and it's incredibly delicious in so many different types of recipes -- from zucchini salad with peaches and avocado and all sorts of stir-fries, to chile zucchini bread and even chocolate zucchini cake!

We see it sliced, grated, chopped, grilled, roasted, sautéed, and so on.

Along with a handful of other fresh ingredients, it's one of the stars of this delicious vegetarian Southwestern Casserole with a kick.

This is one very hearty vegetarian casserole, with a spicy Latin flavor profile. I think you’ll love it!

Jump to:

• The Key Ingredients
• How to Make this Southwestern Casserole
• Variations
• Can you make it ahead?
• Serving Suggestions
• Can you freeze it?
• More Delicious Vegetarian Casseroles
• Vegetarian Southwestern Casserole

The Key Ingredients

• zucchini - Feel free to use yellow zucchini if you see it, and a combination of yellow and green would be pretty. The larger the better for this recipe, as they become layers, almost like lasanga noodles.
• mushrooms - To save time, you can purchase pre-sliced mushrooms. (When they are pre-sliced you still need to wash them!)
• black beans - I make Mexican Black Beans for the casserole, though you can use any black beans you like. Be sure to drain them well if you use canned beans.
• avocado - Ripe avocados should yield to firm gentle pressure. They will feel slightly soft but not mushy to the touch. The avocado is a delicious topping on this casserole. If however, it's off season, and you can't find a good avocado, it's better to skip it.
• jalapeños - These will go both in the filling and on top of the casserole. The heat level of jalapeños can vary from pepper, so taste them first to know what you're dealing with.. Look for firm, deeply colored shiny peppers.
• chipotles in adobo sauce - Chipotle Peppers in Adobo Sauce are jalapeño chiles that have been dried, smoked and packed in a sauce made of tomatoes and spices. They come in a can and you should be able to find it in any major grocery store. Substitution: You can substitute with chili paste if you'd like.

How to Make this Southwestern Casserole

- Slice zucchini thinly, lengthwise, about ¼ inch thick. (The easiest way to do this is to use a mandoline. If you don’t have one, use a Chef’s knife.)

- Coat the zucchini slices with olive oil and season them generously with salt and pepper. Add them to a very hot grill and cook until they're tender and nicely browned, about 2 minutes per side.

Recipe tip: Grilling the zucchini adds a lot of the smoky flavor to this recipe. You can however, sauté the zucchini in a cast iron skillet and it will acquire a lovely caramelization which also adds delicious flavor.

- In a small bowl, combine jalapeño, garlic, chipotles in adobo sauce and cumin. (It's this, the beans and garnishes that really give this Southwestern Casserole its Latin vibe.)

- Add the onion to a large sauté pan lightly coated with oil over medium heat. Cook until soft and golden, about 20 minutes. Then add the seasoning mixture, stir, and cook until aromatic, about 30 seconds.

- Turn the heat up and add half of the mushrooms. Stirring often, sauté until they’ve shrunk and softened, and then add the rest, and continue to cook until they're golden, about 10 minutes. Mix in the beans and season to taste with salt and pepper.

- Assemble all of the prepared ingredients into a 9 x 13 x 2 inch baking dish as follows: ⅓ of the onion-mushroom mixture, grilled zucchini, ½ cup of the Cheddar and ¼ cup of the Pepper Jack cheese. Repeat this layering process twice more, with extra cheese on top.

- Place the baking dish in a preheated 375°F oven and bake for 20 minutes. Remove from the oven, cool a bit, and garnish.

Recipe tip: Avocado, cilantro and jalapeño slices are added to the top of the Southwestern Casserole for the garnish. It brightens up the whole dish and adds great fresh flavor. To save time, you can serve them on the side.

(More detailed instructions are in the recipe card below.)

Variations

• spicier version. For more heat in this recipe, do not remove all (or any) of the jalapeño seeds and/or those from the chipotles in adobo sauce.
• mild version. Use less, or omit the chipotles in adobo sauce and jalapeños. To keep the smoky flavor the chipoltes bring, you can use about 1 ½ teaspoons of smoked paprika in its place. Also, use all Cheddar cheese instead of using part Pepper Jack.

Can you make it ahead?

Yes! There are a couple options:

• You can grill the zucchini and sauté the vegetables up to one day ahead. About an hour before serving, assemble, bake and cool.
• Take it one step further and assemble the casserole a day ahead of time. The next day, about 45 minutes before you want to serve, bake it. 

Serving Suggestions

Below are a handful of dishes the Southwestern would be great to serve with.

Can you freeze it?

Yes! Let it cool completely before freezing. It works very well to cut the casserole into portions, and then freeze them separately. This way, you can grab just enough for one or two, if you’d like.

Be sure it’s wrapped very tightly to avoid air getting in. It can be frozen for up to three weeks. (I wouldn’t recommend freezing the whole casserole, but it’s great for leftovers.)

More Delicious Vegetarian Casseroles

• Smashed Potato Casserole
• Lasagna with Swiss Chard
• Vegetarian Potato Moussaka
• Hatch Chile Cornbread Casserole

I hope you love this Vegetarian Southwestern Casserole as much as my family and I do!

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