Garlic Herb Zucchini Pesto Orzo Casserole

I never thought to combine zucchini and pesto with orzo until I ran out of regular pasta one night. Growing up, my mom always stuck to basic spaghetti with marinara, and anything else felt like uncharted territory.

But sometimes the best recipes come from those “what’s left in the pantry?” moments. This casserole started as a happy accident, and now it’s one of those dishes I make when I want something comforting but not too heavy. The zucchini keeps it fresh, while the pesto adds just enough flavor to make it interesting. My kids actually ask for seconds, which is saying something when it comes to vegetables.

What Kind of Zucchini Should I Use?

When shopping for zucchini, look for ones that are medium-sized, about 6-8 inches long – these tend to have the best flavor and texture for casseroles. The really large, overgrown zucchini you might find in your garden can be a bit watery and seedy, so it’s best to skip those for this recipe. You can actually use either green zucchini or yellow summer squash here, as they cook similarly and have almost identical flavors. Just make sure your zucchini feels firm when you give it a gentle squeeze and has smooth, unblemished skin. If you’re prepping ahead, store your zucchini in the crisper drawer of your fridge and use it within 4-5 days for the best results.

Options for Substitutions

This cozy casserole is pretty adaptable and here are some easy swaps you can try:

• Orzo: While orzo works best for the texture of this dish, you can use other small pasta shapes like small shells, ditalini, or even Israeli couscous. Just check the cooking time on the package as it might need adjusting.
• Zucchini: Yellow summer squash works perfectly here, but you could also try other quick-cooking vegetables like chopped asparagus, broccoli florets, or even fresh spinach.
• Pesto: Store-bought pesto is convenient, but you can use any variety – try sun-dried tomato pesto or even a homemade version. If you’re in a pinch, you can make a quick version with basil, olive oil, garlic, and parmesan.
• Shallot: No shallots? Use half a small onion or even 2-3 green onions instead.
• Cheese: Any melting cheese works well here – try mozzarella, provolone, or fontina. For a stronger flavor, mix in some parmesan or pecorino romano.
• Italian seasoning: If you don’t have Italian seasoning, use a mix of dried basil, oregano, and thyme. About 1 teaspoon of each will do the trick.

Watch Out for These Mistakes While Cooking

The biggest challenge when cooking orzo casserole is getting the liquid ratio right – too much water will make it soupy, while too little will leave you with undercooked pasta, so stick precisely to the 2.5 cups of water called for in the recipe.

Many cooks make the mistake of not sautéing the zucchini long enough – make sure to cook it until most of its moisture has evaporated (about 5-7 minutes), otherwise your casserole might end up watery.

A common error is stirring too much once the orzo starts cooking – instead, give it just one or two gentle stirs during cooking to prevent the pasta from sticking to the bottom while still allowing it to develop a nice crust.

For the best texture, let the casserole rest for 5-10 minutes after baking – this allows the cheese to set slightly and makes it easier to serve neat portions.

What to Serve With Zucchini Pesto Orzo Casserole?

This cozy pasta casserole pairs really well with simple sides that balance out its rich, herby flavors. A fresh arugula salad with lemon dressing makes a perfect light companion, cutting through the creamy cheese and pesto. If you’re looking to add some protein, grilled chicken breast or Italian-style meatballs would fit right in with the Mediterranean flavors. For a complete meal, serve some garlic-roasted cherry tomatoes on the side – they’ll complement the pesto and add a nice pop of color to your plate.

Storage Instructions

Keep Fresh: This zucchini pesto orzo casserole is perfect for leftovers! Pop it in an airtight container and keep it in the fridge for up to 4 days. The flavors actually get better as they meld together, making it a great make-ahead meal for busy weeknights.

Freeze: Want to save some for later? Let the casserole cool completely, then portion it into freezer-safe containers. It’ll keep well in the freezer for up to 3 months. Just remember that zucchini might become a bit softer after freezing, but the taste will still be great!

Reheat: To warm up your casserole, pop it in the microwave for a few minutes, stirring halfway through. If it seems a bit dry, add a splash of water or broth. For oven reheating, cover with foil and warm at 350°F for about 20 minutes, or until heated through. Give it a good stir before serving to redistribute that yummy pesto sauce!

Preparation Time	10-15 minutes
Cooking Time	39-41 minutes
Total Time	49-56 minutes
Level of Difficulty	Easy

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2100-2300
• Protein: 80-90 g
• Fat: 130-150 g
• Carbohydrates: 180-200 g

Ingredients

• 2 medium squash (zucchini or yellow variety)
• 1 tbsp olive oil
• 2 large garlic cloves, minced
• 1 medium shallot, chopped
• 1 tbsp italian herb blend
• 1/4 tsp ground cayenne
• 1/4 tsp salt
• 1/4 tsp black pepper
• 1 tsp low-sodium cajun spice mix
• 1 1/2 cups grated cheese
• 8 oz prepared pesto
• 1 lb orzo pasta
• 2 1/2 cups water

Step 1: Roast the Vegetables

• 2 medium squash (zucchini or yellow variety)
• 1 tbsp olive oil
• 2 large garlic cloves, minced
• 1 medium shallot, chopped
• 1 tbsp Italian herb blend
• 1/4 tsp ground cayenne
• 1/4 tsp salt
• 1/4 tsp black pepper

Preheat your oven to 400°F (200°C).

In a 9×13 inch baking dish, combine the sliced zucchini (or yellow squash), olive oil, minced garlic, chopped shallot, Italian herb blend, ground cayenne, salt, and black pepper.

Mix everything well to ensure the vegetables are evenly coated with the oil and seasonings.

Roast in the oven for 15 minutes, until the squash begins to soften and the aromatics are fragrant.

Step 2: Add Orzo, Pesto, and Spices

• 1 lb orzo pasta
• 8 oz prepared pesto
• 1 tsp low-sodium Cajun spice mix
• 2 1/2 cups water
• roasted vegetables from Step 1

Remove the baking dish from the oven.

To the roasted vegetables, add the orzo pasta, prepared pesto, and Cajun spice mix.

Pour 2 1/2 cups of water over everything in the dish and stir to combine all ingredients thoroughly.

This helps the flavors meld as the orzo cooks right in the pan.

Step 3: Bake Pasta Mixture

• orzo and vegetable mixture from Step 2

Return the baking dish to the oven and bake for 14 to 16 minutes, or until most of the water has been absorbed by the orzo.

You might notice a little water remaining at the bottom of the dish; that’s perfectly fine.

Step 4: Add the Cheese and Final Bake

• 1 1/2 cups grated cheese
• baked orzo mixture from Step 3

Give the pasta mixture a good stir to incorporate any remaining liquid.

Sprinkle the grated cheese evenly over the top.

Return the dish to the oven and bake for another 10 minutes, or until the cheese has melted and the sauce is bubbling.

If you notice excess oil from the pesto rising to the top, you can drain it off for a lighter finish.

I like to let the dish sit for a couple of minutes after baking – it makes serving easier and helps everything set.

Step 5: Garnish and Serve

Remove the baked orzo from the oven and let it cool for a few minutes.

For a fresh finish, top with fresh basil or herbs if desired before serving.

Enjoy your creamy, cheesy orzo bake!