Cheesy Baked Zucchini Casserole

Cheesy Baked Zucchini Casserole

This cheesy baked Zucchini Casserole is out of this world amazing!

Cheesy Baked Zucchini Casserole

Zucchini Casserole

This cheesy baked Zucchini Casserole is out of this world amazing! NOTE: Allow an extra 15-40 minutes for salted zucchini to sit before patting dry. This will help prevent soggy squash and yield best results.

  • Course: side dish
  • Cuisine: american, vegetarian
  • Prep time: 20 minutes
  • Cook time: 30 minutes
  • Total time: 50 minutes
  • Servings: 8 servings


  • 1 lb zucchini squash
  • 2 cups finely diced onion
  • 1 tsp olive oil
  • 3 TBSP butter
  • 3 TBSP all-purpose flour
  • 3/4 cup milk (warmed via microwave or stovetop)
  • 1/4 tsp salt plus extra as needed/desired
  • 1/4 tsp black pepper plus extra to taste
  • 1/4 tsp garlic powder
  • 1/8 tsp ground nutmeg
  • 4 oz freshly grated Gruyere cheese
  • 4 oz freshly grated Gouda cheese


  • 1/2 cup Italian seasoned breadcrumbs (panko or regular)
  • 1 TBSP unsalted butter



  1. Measure out all your ingredients, this will come in handy as the sauce comes together fast!
  2. Discard the ends, then slice each zuchini into 1/4-inch discs. Take care not to slice them too thin or they will get too soft/mushy while cooking. If bite-sized forkfuls are preferred, feel free to cut the rounds in half lenghtwise.
  3. Sprinkle zucchini slices with sea salt and place on an absorbent (clean) dish towel. Allow to sit a minimum of 15 minutes, though 30-40 minutes will help draw out more water. You’ll notice water droplets on top of the slices when this happens. Pat dry on both sides using paper towels to remove as much moisture as possible. No one likes soggy squash!
  4. Preheat oven to 375°F


  1. Heat a medium pot to medium-high heat with 1 tsp olive oil. Sauté onions, stirring occasionally. Continue cooking until onions are golden brown and tender.
  2. Move onions to the side (if possible) and add 3 TBSP butter. Once melted, add the flour, whisking with a metal whisk constantly for 2 minutes while it bubbles and darkens in color. This roux will thicken the sauce. Pour heated milk into the butter-flour mixture and whisk well. Bring to a light boil, whisking constantly for 1 minute or until the mixture has thickened.
  3. Remove from heat and add salt, pepper, garlic powder, and nutmeg. Working in 2-3 batches, add half the Gruyere cheese and all of the Gouda cheese, whisking in between each batch to gently melt the cheese.
  4. Arrange zucchini in a medium baking dish and top with your sauce. Sprinkle with remaining gruyere cheese. Bake at 375°F for approx. 20-25 minutes, until the top is golden brown and the zucchini has reached ideal tenderness.
  5. While the casserole bakes, add Italian-seasoned breadcrumbs to a heated pan/skillet with butter and gently toast until golden. Carefully sprinkle over casserole once ready and finish remaining bake time.
  6. Enjoy hot!

Recipe Notes

No panko or breadcrumbs? No problem! Crushed Ritz crackers also make a tasty topping for your zucchini casserole.

Nutrition Facts below are estimated using an online recipe nutrition calculator. Adjust as needed and enjoy!


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