Mom’s Cheddar Zucchini, Tomato, & Onion Gratin

I grew up on this dish. Every summer, my mom would head out to the garden and bring in a huge zucchini and a couple of perfectly ripe tomatoes. She’d slice them up and throw them in a baking dish with some sweet onion, and then she’d top it all with a good amount of grated cheddar. Then she’d bake it until the veggies were tender, the cheddar oozey, the family happy.

Mom's Cheddar Zucchini, Tomato, & Onion Gratin recipe - so easy! The quintessential summer side. Fresh-from-the-garden zucchini, tomatoes, and onions layered and covered with cheddar, then baked until tender and cheesy. Vegetarian with vegan option.

It seems like such a simple dish (and it is), but I’ve screwed it up an embarrassing number of times. Basically, the pattern goes like this: I forget important details from season to season, fail an attempt (bake it covered, for too long, not long enough …), and then I call my mom once again to ask for directions.

So I’m actually kind of proud that I finally remembered it all on my own this year. And it’s just as I remembered: the dish my mom would whip up every other day come August, a sure sign that we’re smack in the middle of the dog days of summer.

Mom's Cheddar Zucchini, Tomato, & Onion Gratin recipe - so easy! The quintessential summer side. Fresh-from-the-garden zucchini, tomatoes, and onions layered and covered with cheddar, then baked until tender and cheesy. Vegetarian with vegan option.

And now I’m going to save the recipe for posterity in this here food blog so that I never, ever forget. Yes, I want to share this wonderful little dish with you, but I’m also pretty happy to have it written down for good. But it’s still good to call mom to let her know I’m thinking of her. 🙂

Make it vegan

From time to time, I’ll make a vegan version by skipping the cheddar and drizzling the veggies with a tablespoon or so of olive oil, then dusting with salt and pepper and baking as usual. Also wonderful! Mozzarella Daiya is also great in lieu of cheddar, though I use it a bit more sparingly.

4 from 2 votes

Mom's Cheddar Zucchini, Tomato, & Onion Gratin

Prep: 10 minutes
Cook: 30 minutes
Total: 40 minutes
Author: Kare
Yield: 4 -6
The quintessential summer side. Fresh-from-the-garden zucchini, tomatoes, and onions layered and covered with cheddar, then baked until tender and cheesy.

Ingredients

  • 1 large zucchini (sliced 1/4-inch thick)
  • 2 large tomatoes (sliced 1/4-inch thick)
  • 1 large white (yellow, or sweet onion, sliced 1/4-inch thick)
  • 1 cup grated sharp cheddar cheese
  • Salt and pepper to taste
  • Fresh basil for topping/garnish (if desired)

Instructions

  • Preheat oven to 400 degrees Fahrenheit.
  • In an 8" x 8" baking dish, lay the zucchini, then the onions, then the tomatoes. Top with a pinch of salt and pepper, then sprinkle the cheddar cheese on top.
  • Bake uncovered for 30 minutes, or until the vegetables are tender and the cheese melted.
  • Top with fresh basil if desired and serve.