Old-Fashioned Zucchini Casserole is a creamy, cheesy comfort-food classic that comes together in just 10 minutes of prep. Made with fresh vegetables and simple pantry staples, it's a filling recipe that always seems to disappear fast. It's the kind of crowd-pleasing side dish that transforms zucchini into something even kids get excited to eat.
Old-Fashioned Zucchini Casserole Recipe Essentials
- 🍽️ Course: Side dish
- ⏱️ Cooking Time: 30 minutes baking
- 🍴 Servings: 12
- 🧄 Flavor Profile: Savory, cheesy, garlicky, and herb-seasoned with tender zucchini, carrots, onion, and Parmesan.
- 🍚 Best Served With: Roast chicken, grilled steak, ham, pork chops, or as part of a holiday dinner spread.
- 🧊 Make Ahead?: Yes, assemble ahead and refrigerate before baking, or bake in advance and reheat before serving.
Summarize and Save This Content On
This recipe comes straight from my grandma, who used to make it every summer to use up all the zucchini and other vegetables from her garden.
One of her best tricks was adding shredded carrots for a little extra sweetness and color! The biscuit mix gives the casserole a soft, crumbly texture, while the gooey cheese makes you forget you're eating a dish packed with veggies.
Try ground beef zucchini casserole and pork chop zucchini casserole if you're looking for more casseroles or an easy zucchini recipe.
Why You'll Love This Recipe
- It's great for a crowd: This zucchini casserole is made in a 9x13 dish with 12 servings, making it an easy choice for a potluck or gathering. There's plenty to serve a lot of people!
- It's quick and easy: The prep for this recipe is easy and takes only 10 minutes, so you can spend more time enjoying the tender squash and melty cheese instead of cooking.
- It's kid-friendly: There is plenty of seasoning, cheese, and texture in this zucchini squash casserole, making it more appealing to kids and picky eaters.
Ingredients
The key ingredients to making the best-tasting old-fashioned zucchini casserole are listed below!.
- Biscuit mix: Use any brand that you want; they all work perfectly. Don't have any on hand? Make your own! It takes only 1 cup of flour, 1 ½ teaspoons of baking powder, ½ teaspoon of salt, and 1 tablespoon of butter.
- Zucchini: Thin slices are best here to ensure they fully cook. I recommend using the slicing attachment of a food processor for consistency, if you have it. I treat the zucchini the same when I make these crispy zucchini bites.
- Parmesan and Colby Jack: Both of these cheeses melt better and have better flavor when freshly shredded. Cheddar and Monterey Jack are easy substitutes for Colby Jack.
- Carrots: Feel free to shred them yourself, or pick up shredded matchstick carrots from the produce section. It's one of my favorite shortcuts for this recipe.
See the recipe card below for exact ingredient amounts, nutritional information, and detailed instructions.
Variations
- Add a protein: Turn this into a complete and filling meal by adding a protein like shredded chicken, diced ham, or even ground beef.
- Use more veggies: Add corn, diced bell peppers, or even slices of mushrooms (or a combination of them) to the casserole for more texture and nutrition!
- Gluten-free: Trade the biscuit mix for a gluten-free version. It's an even 1:1 swap! I recommend Bob's Red Mill or a similar brand.
How to Make Easy Zucchini Casserole with Biscuit Mix
Grease your casserole dish with nonstick cooking spray and preheat your oven to 350°F before you get started on this old-fashioned zucchini casserole recipe.
Step 1: Prepare the egg mixture. Combine the eggs with the onions, Parmesan, oil, and spices in a bowl.
Step 2: Add the veggies and biscuit mix. Add the zucchini, carrots, and Bisquick. Once everything is fully coated, transfer it to the casserole dish in an even layer.
Step 3: Bake it. Place it into the oven and bake it for about 30 minutes, or until the top starts to brown.
Step 4: Top with cheese. Sprinkle the Colby Jack on top and let it fully melt. Enjoy the tender, cheesy zucchini with garlic chicken thighs!
Expert Tips
- Slice the zucchini evenly: Ensure that you slice the zucchini as evenly as possible so they all cook at the same rate. Otherwise, you'll be left with mushy, overcooked pieces and hard, undercooked pieces.
- Spread the zucchini gently: There's no need to press the zucchini hard into the pan. Spread the slices gently in the casserole dish so you don't overpack the pan.
- Rest after baking for easier serving: Allow your baked zucchini casserole time to rest after it comes out of the oven so it can firm up. It's easier to slice and less likely to fall apart and become a mess.
- Storing: Transfer any leftovers into an airtight container and keep them in the refrigerator for up to 4 days.
- Reheating leftovers: Skip the microwave, if possible, as it can make the zucchini rubbery. Instead, bake covered in foil at 350F for about 20 minutes, and then uncovered for 5 minutes to crisp up the cheese.
Another casserole where zucchini is the star is this zucchini casserole stuffing.
Serving Suggestions
- Protein pairings: Combine this zucchini casserole with Bisquick and this broiled pork chops to create a delicious, winning meal. Baked honey mustard ham is another one of my favorite pairings!
- Sunday dinner: This casserole is the perfect side dish to add to your Sunday dinner spread. There's plenty to go around if you're expecting company!
- Lighter sides: If you're looking for some refreshing sides to serve with old-fashioned zucchini casserole, old-fashioned cucumbers and onions in vinegar are delightfully bright and crunchy.
Old-Fashioned Zucchini Casserole Recipe FAQs
Zucchini releases moisture as it bakes, which can sometimes make the casserole soggy. If the zucchini is very wet after slicing, let the mixture rest for about 10 minutes, then drain any excess water before assembling the casserole.
Sure! It works perfectly as an even swap, or you can use a medley of both varieties for flavor, texture, and color.
Sure! Wrap it tightly and freeze the old-fashioned zucchini casserole for up to 3 months. You may bake it from frozen at 350F for 45-50 minutes.
Yes, you can. Assemble the casserole, tightly cover it with foil, and refrigerate it unbaked for up to 24 hours. If you bake it from cold, add 5-10 minutes to the cooking time.
More Delicious Zucchini Recipes
Do you have a lot of zucchini to use up? Try some of these next!
If you try this recipe and love it please leave a star rating in the recipe card below or even better, drop a review in the comment section. I always appreciate your feedback. Be sure to follow along with me on Facebook, Pinterest, and YouTube for more easy recipes!
Old-Fashioned Zucchini Casserole
Equipment
Ingredients
- 4 large eggs beaten
- ½ cup onion diced
- ½ cup Parmesan cheese grated or shredded
- ½ cup oil
- 1 ½ teaspoon Italian seasoning
- ½ teaspoon salt
- 1 teaspoon pepper
- 1 teaspoon garlic powder
- 1 cup biscuit mix
- 3 ½ cups zucchini with peel, thinly-sliced
- ¾ cup carrot shredded or match stick
- 1 cup colby jack cheese shredded
Instructions
- Preheat your oven to 350 degrees F.
- Prepare a 13x9 inch pan with cooking spray and set aside.
- In a large bowl combine eggs, onion, Parmesan cheese, oil, Italian seasoning, salt, pepper and garlic powder.
- Stir with a whisk until blended.
- Add biscuit mix, carrots and zucchini.
- Stir gently until zucchini is evenly coated.
- Dump into your prepared pan.
- Bake for about 30 minutes and lightly browned.
- Top with Colby Jack cheese and let it sit 5 minutes to melt.
Video
Notes
- If your zucchini seems extra watery, let it sit for about 10 minutes after slicing, then drain off any excess liquid. This helps keep the casserole from becoming soggy.
- Try to slice the zucchini into even pieces so they cook at the same rate. Uniform slices help prevent some pieces from becoming mushy while others stay undercooked.
- Let the casserole rest for 10-15 minutes after baking. This gives it time to firm up, making it easier to slice and serve neatly.
nan says
Loved this recipe. Will Make again. Next time might add some meat..*****
Karin and Ken says
Please let me know how it goes adding meat if you try it. I’ve been making this recipe so long and I've never tried that. Never even occurred to me. I can’t thank you enough for taking the time to comment!! All the best. Karin
Kiesha says
Thank you for this heart warming dish! I just live zucchini. In fact I think I'll make it again tomorrow. Thanks again. Love the cheesy mix with the veggies. Sometimes I throw some leftovers in an omelette! So amazing!
Karin and Ken says
That you for the suggestion. I’m going to try that myself! All the best. Karin
Marla says
Can this be frozen?
Sheri says
Am in the middle of making this recipe and in the ingredients you show a 1/2 grated or shredded parmesan cheese to be mixed in with the batter. But at the very bottom of the ingredients you show a 1/3 cup parmesan as well, but never mention when or how it is to be used????s
Karin and Ken says
I apologize for the confusion! Please put 1/2 cup Parmesan with the zucchini and biscuit mixture. The 1/3 cup Parmesan goes all over the top of the casserole. I hope you enjoy this casserole as much as we do. I apologize again for not being more clear in the instructions. Take care and all the best. Karin