Zucchini gets a whole lot more exciting when it’s turned into Cheesy Zucchini Casserole! If you’re looking for a tasty way to use up your zucchini, this recipe delivers. The zucchini is smothered in a rich blend of cheddar and parmesan, creating a cheesy, comforting side dish that’s hard to resist. But it’s the buttery Ritz cracker topping that really steals the show, adding the perfect crunch on top. It’s a crowd-pleaser that’s easy to make.

For yellow squash, try our squash casserole!

Why Our Recipe

  • Creamy zucchini meets cheesy goodness.
  • Buttery Ritz crackers make for the perfect topping.
  • Easy to make for a side dish or potluck.
An overhead view of a casserole dish with zucchini casserole, with a corner serving removed.

Smelling all that yummy onion and cheesy flavor wafting through your kitchen will bring hungry tummies to the table. The sharp bite of cheddar cheese with the nutty, salty flavor of parmesan cheese takes zucchini from the squash on your counter to veggie nirvana. Mixing sour cream with cheddar and parmesan cheese creates a subtlely tangy sauce, and provides structure to the sauce to keep it from being watery – because nobody wants a watery sauce. And because zucchini cooks down soft, the buttery cracker topping keeps texture in this dish while enhancing the flavor with a layer of salty, nutty goodness. Use up some of the zucchini from your garden or grab some from the grocery store, because this easy casserole will be a new favorite on your menu.

Ingredient Notes

An image of raw, fresh and dry ingredients to use in zucchini casserole.
  • Zucchini: 1 pound sliced zucchini is approximately 2 zucchini (cucumber-sized), so you need 6-7 regular-sized zucchini. If you’re dealing with larger zucchini, you might want to scoop out the seeds before slicing.
  • White Onion: Can be substituted with a yellow or sweet onion.
  • Sour Cream: Full-fat sour cream will give your sauce the rich density it needs. Greek yogurt can be used as a substitute if needed—use the same amount (8 ounces)
  • Cheese: We recommend sharp cheddar for the best flavor and freshly grated parmesan cheese for the best melting.
  • Crackers: Ritz is our cracker topping of choice for that buttery, salty goodness. You could always use 1 cup of Panko bread crumbs instead if you don’t have access to Ritz crackers.
  • Garlic Powder: You can substitute with fresh minced garlic, but reduce the amount to 1/2 teaspoon to avoid overpowering the dish.

Drain Your Zucchini

Several of our zucchini recipes don’t require draining the excess liquid from the zucchini, but in this casserole draining that water is required. Cook the zucchini and onions in the skillet until the zucchini just starts to soften, about 7-10 minutes. Then using a mesh strainer, drain out any liquid that has been released during the cooking.

This step ensures that the sour cream and cheese mixture sticks to the zucchini, giving you that rich, creamy consistency you want. Skipping this step will result in a watery casserole Just no.

A portion of zucchini casserole on a plate with a fork getting ready to take a bite.

Make Ahead Instructions

For a potluck, a large gathering, or a big dinner, you can fully assemble the casserole the night before. Prepare everything up until the baking step, cover it tightly with foil or plastic wrap, and refrigerate overnight. On the day of your event, bake it just before you head out. If you need to transport it, cover the baked casserole with foil to keep it warm. You can also reheat it at your destination by placing it in a 325°F oven for 10-15 minutes, and broil for 4-5 minutes to crisp up the topping before serving.

Storage and Reheating Instructions

Refrigerate leftovers in an airtight container for up to 3 days.

Reheat portions in the oven at 325 degrees in an oven-safe dish until heated through. Then turn on the broiler for 4-5 minutes to crisp up the cracker topping.

Reheat in the microwave by placing a portion on a microwave-safe plate and heat in 30-second increments on high until warmed through. Keep in mind that the cracker topping will lose its crispiness in the microwave.

More delicious ways to use zucchini…