Healthy Vegetarian Baked Lentil Casserole: Easy & Cheesy

There's a reason people fell in love with casseroles – they are easy to make, feed a lot of people, and are cheap and delicious. This red lentil casserole is a deliciously satisfying dish packed with protein-rich lentils, umami-rich mushrooms, and nutrient-dense zucchini. Topped with melty cheddar cheese, it’s a hearty, one-dish wonder that aligns with our sustainable food choices.

For the full recipe and nutritional information, check out the recipe card below for the dish that makes a couple of easy weeknight meals. Check out or video here too:

Why You'll Love This Lentil Casserole

✅ Sustainably Sourced – Lentils and vegetables have a low carbon footprint compared to meat-based casseroles.
 
✅ High in Plant-Based Protein – Red lentils provide an excellent source of protein, dietary fiber, and iron.

✅ Minimal Food Waste – We make our own vegetable broth from cooking scraps, but feel free to use chicken broth if that's what you have handy.

✅ Delicious and Easy – A layer of cheesy goodness makes this meal appetizing to even the most skeptical food critic

✅ Budget Friendly – Lentils are incredibly cost-effective. As well as carrots, onions, mushrooms, celery, and all of the other ingredients come in around $8 for six servings. 

✅ Healthy and Versatile – My favorite thing about this casserole is that it uses whole foods, whereas other casserole recipes use ultra-processed soup bases.

Casseroles are the ultimate comfort food—warm, nourishing, and perfect for meal prepping. While most casseroles are made with condensed soup or mayonnaise, this lentil casserole is healthy and eco-friendly. Lentils are an iron and fiber-rich protein source that require significantly less water and land compared to animal proteins. 

Plus, they’re an affordable pantry staple, making this recipe both budget-friendly and nutritious. Another great thing about this lentil bake is that you can make it with whatever vegetables you have in your refrigerator. While we used mushrooms and zucchini, feel free to use whatever you've got handy.  

Finally, this easy weeknight meal makes six servings, meaning you cook once for twenty minutes and then have food for the week!

Print Recipe

Veggie Lentil Casserole

Prep Time5 minutes mins

Cook Time25 minutes mins

Course: Main Course

Servings: 6

Calories: 340kcal

Cost: 8

Ingredients

• 1 tbsp olive oil
• 1 cup red lentils rinsed
• 2 cups vegetable stock / vegetable broth
• 1 onion finely chopped
• 2 cloves garlic minced
• 1 zucchini grated
• 1 cup mushrooms chopped
• 1 tsp Italian seasoning
• 1 tsp cumin
• 1 cup cheddar cheese shredded
• Salt & Pepper to Taste

Instructions

• Sauté the Aromatics: In a large pan, sauté the onions in a drizzle of olive oil over medium heat until translucent. Add the minced garlic and stir for another minute.
• Cook the Lentils: Pour in the dry lentils and then deglaze the pan with vegetable stock. Simmer for 10-12 minutes until softened or al dente, stirring occasionally. Option here to add a bay leaf for extra flavor.
• Add the Vegetables: Stir in the grated zucchini and chopped mushrooms to the cooked lentils, letting them cook for another 5 minutes until softened. The mixture should be thick but still moist. Option to add a little cheese into the mixture so you get cheese in every bite.
• Assemble the Casserole: Preheat the oven to 375°F (190°C). Transfer the lentil mixture into a casserole dish and spread evenly.
• Top with Cheddar Cheese: Leave the cheese out at room temperature to it's soft to grate. Then sprinkle the shredded cheddar evenly over the casserole for a rich, cheesy topping.
• Bake Until Golden: Bake uncovered for 15-20 minutes or until the cheese melts and is bubbly and golden brown. Let it rest for a few minutes before serving.

Lentil Casserole Serving Suggestions

• Serve over brown rice or these rice alternatives. White rice works fine too. 
• Pair with a simple green salad and crusty bread for a balanced meal.
• Serve on top of whole-grain bread, roasted potatoes, or sweet potatoes for extra heartiness.
• Top with fresh herbs like fresh parsley for a pretty appearance

Lentil Casserole Ingredient Swaps and Enhancements

Serve with hot sauce if you like a little spice or season with ancho chili powder for a spicier flavor. 

Our nutritionals were based on the above recipe formulation. So if you change it, keep in mind you may change the nutritional content.

You can use whatever vegetables you have on hand. Swap a red onion for the yellow onion or bell peppers or fresh spinach in place of the zucchini. 

I used red lentils here for a softer texture, but you can use green lentils or brown lentils if ou prefer. 

If you're vegan or lactose intolerant, you can swap for a vegan cheese. 

How to Store the Lentil Casserole

You can store this in the baking dish or in an airtight container. If you're meal prepping, you can put a base of rice and then add the lentil casserole to create individual portions. Store leftovers in the fridge for up to 3 days or freeze for a quick weeknight meal.

You can also check out our post here for eco friendly food storage containers.

Stay Up to Date with More Sustainable Recipes 

This red lentil casserole is proof that comfort food can be delicious, nourishing, and sustainable. Try it tonight and enjoy a meal that’s good for you and the planet!

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