Zucchini Casserole

Posted on November 28, 2025

Modified: November 28, 2025

A golden-brown Zucchini Casserole baked in a glass dish, with a slice being lifted out to reveal layers of zucchini, rice, and cheese.

I remember the first time I made this Creamy Parmesan Zucchini Casserole. The aroma of garlic and cheese filled my kitchen, instantly making the house feel more like a home. It’s more than just a recipe to me; it’s a warm hug on a plate. This dish has the comforting, nostalgic feel of my favorite hashbrown casserole, but with a touch of elegance that makes any meal feel special. The combination of tender zucchini, a luxuriously creamy sauce, and that golden, crunchy topping is pure magic.\n\n## My Favorite Things About Zucchini Casserole\nWhat I adore most about this Zucchini Casserole is how it delivers such impressive flavor with minimal fuss. With just 20 minutes of prep and 30 minutes of cook time, it’s my go-to for weeknight dinners and potlucks alike. The ingredients are simple, but they come together beautifully—the nutty Gruyère and sharp Parmesan create a sauce that feels incredibly decadent, transforming humble zucchini into the star of the show. It’s a dish that proves comfort food can also feel a little fancy.\n\n## What Goes Into My Favorite Zucchini Casserole\nFor this Zucchini Casserole, I always choose firm, smaller zucchini for the best texture. The real secret, however, is using both Gruyère and Parmesan cheese. Gruyère melts into a beautifully smooth, nutty sauce that reminds me of the richness in a great seafood Alfredo casserole, while Parmesan adds a sharp, salty bite.\n\n\n

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Overhead view of Vietnamese Pho with rice noodles, beef, fresh herbs, bean sprouts, and chili in a rustic bowl.

Emma

Authentic Vietnamese Beef Pho with Rice Noodles (Phở Bò)

This comprehensive recipe guides you through creating a rich, aromatic, and deeply satisfying Vietnamese Beef Pho broth from scratch, served with tender beef slices, slippery rice noodles, and a vibrant array of fresh garnishes.

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Prep Time 45

Cook Time 4

Total Time 4 45

Servings: 6 servings

Course: Main Course

Cuisine: Vietnamese

Calories: 620

Ingredients Equipment Method Notes

Ingredients

For the Broth (Nước Lèo)

3-4 lbs Beef marrow bones cut into 2-3 inch pieces
1-2 lbs Beef knuckle bones optional, for more collagen
1 lb Beef oxtail optional, for richness
2 large Yellow onions unpeeled, halved
1 large piece Ginger 4-5 inches, unpeeled, halved lengthwise
8-10 pods Star anise
3-4 Cinnamon sticks 3-inch
2-3 Black cardamom pods
1 tsp Cloves whole
1 tsp Fennel seeds
1 tsp Coriander seeds
1.5-2 oz Rock sugar (đường phèn) 45-60g, adjust to taste
4-6 tbsp Fish sauce adjust to taste
1 tbsp Salt or to taste
8-10 quarts Water 7.5-9.5 liters

For the Beef (Thịt Bò)

1.5 lbs Beef brisket lean, boneless, for simmering in broth
1 lb Beef eye round or sirloin very thinly sliced against the grain, for rare beef

For the Noodles (Bánh Phở)

1.5 lbs Dried flat rice noodles (Bánh Phở) medium width (about 1/4 inch / 6mm)

For the Garnishes (Rau Thơm) and Condiments

1 small Yellow onion thinly sliced
4-6 stalks Green onions thinly sliced
1 bunch Cilantro chopped
1 bunch Thai basil fresh leaves
1 bag Bean sprouts 8-12 oz / 225-340g
2 Lime cut into wedges
1-2 Jalapeño or Serrano peppers thinly sliced (optional)
To taste Hoisin sauce for serving
To taste Sriracha sauce for serving

Equipment

Large Stock Pot (12-quart / 11-liter minimum)
Roasting Pan or Baking Sheet
Fine-Mesh Sieve or Colander
Ladle
Cutting Board
Sharp Knife
Small saucepan
Spice Bag or Cheesecloth

Method

Prepare the Broth (Day 1 - or at least 4 hours ahead)

Rinse beef bones thoroughly under cold water. Place bones in a large stock pot, cover completely with cold water, and bring to a rolling boil over high heat. Boil vigorously for 10-15 minutes, actively skimming off any foam and impurities that rise to the surface. This step is crucial for a clean, clear broth. Drain the bones in a colander and rinse each bone individually under cold water to remove any remaining scum. Clean the stock pot thoroughly.
Place the halved unpeeled yellow onions and ginger directly on a baking sheet. Char under a broiler or directly over an open flame (gas burner) until softened and slightly blackened in spots, about 10-15 minutes, flipping halfway. The charring adds a deep, smoky flavor and beautiful color to the broth.
In a dry skillet over medium-low heat, gently toast the star anise, cinnamon sticks, black cardamom pods, whole cloves, fennel seeds, and coriander seeds until fragrant, about 2-3 minutes. Be careful not to burn them, as this can make the broth bitter. Transfer the toasted spices to a spice bag or wrap them securely in cheesecloth.
Return the clean, par-boiled bones to the clean stock pot. Add the charred onions and ginger, the spice bag, and 8-10 quarts (7.5-9.5 liters) of fresh cold water. Bring the pot to a gentle boil, then immediately reduce the heat to a very low simmer. Maintain a barely perceptible bubble, as a vigorous boil can make the broth cloudy.
After about 30 minutes of simmering, add the beef brisket to the pot. Continue to skim any additional foam or impurities that rise to the surface during the first hour or two of simmering. Partially cover the pot and simmer for at least 3-4 hours, or up to 6 hours for maximum flavor. The longer it simmers, the richer and more profound the broth will be.
After about 2.5-3 hours of simmering (or when a fork easily pierces it), carefully remove the cooked brisket from the pot. Let it cool slightly, then slice it thinly against the grain and set aside. Continue simmering the bones and aromatics for the remaining time. Once the full simmering time is complete, add the rock sugar, fish sauce, and salt to the broth. Stir until the sugar dissolves. Taste and adjust the seasoning as needed; the broth should be savory, subtly sweet, and well-balanced.
Carefully remove all bones, charred onions, ginger, and the spice bag from the pot. Strain the entire broth through a fine-mesh sieve into another large pot or heat-proof container to ensure a perfectly clear broth. Skim any excess fat from the surface using a ladle or by refrigerating and removing the solidified fat layer (if preparing ahead). Keep the broth hot over low heat until ready to serve.

Prepare Noodles and Garnishes (Just Before Serving)

While the broth is finishing, prepare your garnishes: thinly slice the remaining yellow onion, green onions, cilantro, and jalapeño/serrano peppers (if using). Arrange the fresh Thai basil leaves, bean sprouts, and lime wedges attractively on a large serving platter. Slice the beef eye round or sirloin into paper-thin pieces against the grain. Partially freezing the beef for 20-30 minutes before slicing can make this easier.
Prepare the dried flat rice noodles according to package directions. This typically involves soaking in hot water until pliable (15-20 minutes for thinner noodles) then briefly boiling (1-2 minutes) until al dente. Rinse the cooked noodles thoroughly with cold water to prevent them from sticking, then drain them very well.

Assemble and Serve

For each serving, place a generous portion of the drained rice noodles into a large, deep pho bowl. Arrange slices of the cooked brisket and the very thinly sliced raw eye round/sirloin artistically over the noodles.
Ladle the piping hot broth generously over the noodles and beef. Ensure the broth is hot enough to cook the raw beef slices instantly; they should turn from red to light pink. Serve immediately with the platter of fresh garnishes, hoisin sauce, and Sriracha sauce on the side, allowing each diner to customize their bowl to their liking.

Notes

For an even clearer broth, avoid boiling aggressively; maintain a very gentle simmer throughout the cooking process. The raw beef slices should be paper-thin for optimal cooking in the hot broth. Partially freezing the beef for 20-30 minutes before slicing can make this much easier. Leftover broth can be stored in an airtight container in the refrigerator for 3-4 days or frozen for up to 3 months. Adjust fish sauce and rock sugar to your personal preference for sweet and savory balance. Some prefer more savory, others a touch sweeter.

\n\n## How I Make Zucchini Casserole\nBringing this dish to life is a simple, three-step process I truly enjoy. First, I prepare the zucchini by slicing it and giving it a quick sauté with onion and garlic to build that initial layer of flavor. Next, I whisk together the creamy cheese sauce right on the stovetop until it’s velvety and smooth. The final step is my favorite: assembling it all in a baking dish, which feels as satisfying as layering my classic ground beef and rice casserole. A generous sprinkle of buttery Panko breadcrumbs goes on top before it’s baked to golden perfection.\n\n\n

\n\n\n## My Secrets for Success with Zucchini Casserole\n* Don’t skip salting the zucchini. This step is crucial for drawing out excess water and preventing a soggy casserole.\n* Shred your own cheese. Pre-shredded cheeses have anti-caking agents that can make your sauce gritty.\n* Toast the Panko. For an extra crispy topping, I briefly toast the Panko breadcrumbs in butter before sprinkling them on top.\n\n## How I Serve and Store This Dish\nI love serving this casserole warm from the oven, garnished with a sprinkle of fresh parsley to add a pop of color and freshness. It’s fantastic as a side dish with grilled chicken or fish, but it’s also hearty enough to be the main event for a vegetarian meal. Leftovers are a treat! I store them in an airtight container in the refrigerator for up to three days. To reheat, I recommend popping it back in the oven to help that Panko topping get crispy again.\n\n### Can I prepare this Zucchini Casserole in advance?\nAbsolutely! I often assemble the entire casserole without the Panko topping a day ahead. Just cover it tightly and refrigerate. When you’re ready to eat, sprinkle the buttered Panko on top and bake as directed, adding a few extra minutes to the cook time to ensure it’s heated all the way through.\n\n### Why did my zucchini casserole turn out watery?\nThis is a common issue, and it almost always comes down to the zucchini’s high water content. The most important step to prevent a watery zucchini casserole is to slice, salt, and let the zucchini rest for about 15-20 minutes. This process, called sweating, draws out a surprising amount of liquid. Be sure to pat it dry before cooking.\n\n### What can I use instead of Gruyère cheese?\nWhile Gruyère gives this dish its signature nutty and creamy flavor, you can definitely substitute it if needed. I’ve had great success using other good melting cheeses like Fontina, white cheddar, or even Gouda. Just be sure to choose a cheese that you enjoy the flavor of, as it’s a prominent part of this Zucchini Casserole.\n\n### Is it possible to add protein to this dish?\nYes, this recipe is very adaptable! If I want to make it a more complete one-pan meal, I sometimes stir in shredded rotisserie chicken, cooked ground turkey, or even some crispy bacon bits into the cheese sauce before assembling the casserole. It adds a delicious savory element that complements the creamy zucchini perfectly.\n\nThis recipe holds a special place in my heart, and I truly hope it brings as much joy to your table as it does to mine. If you try this Zucchini Casserole, I’d absolutely love to hear what you think and see your creations in the comments below!\n\nFollow us on Social Media : Facebook and Pinterest

Zucchini Casserole