Summertime Favorites: Tomato and Zucchini Gratin


There’s nothing better than fresh summertime vegetable dishes. As soon as my summer garden starts producing fruits and veggies, I’m always looking for new ways to cook ‘em up!

Of course, tomatoes are at the top of my list. These plump, tasty fruits remind me of summer. If there’s only one thing I plant in the garden, it’s always a variety of tomatoes. Every year I eat as many as I possibly can while they’re in season — it’s when they’re at their most flavorful!

I will absolutely eat nothing but tomato sandwiches, but sometimes it’s nice to fix them in other ways, too. This is especially true when my other plants, like the zucchinis, take off.

This dish combines tomatoes and zucchini, for a slightly healthier, diet-friendly take on the classic potato gratin. I say slightly because it still has plenty of butter and cheese in it. Even still, the zucchini contains significantly fewer carbs than potatoes and is a beneficial nutrient-dense food.

If you have yellow summer squash on hand, you can easily swap the zucchini for summer squash, too. Or try mixing it up and using both!


  • 4 medium-sized zucchini squash
  • 4 or 5 Roma tomatoes
  • ½ of a medium-sized sweet yellow onion
  • 1 cup of milk
  • ⅔ cup of shredded cheddar cheese
  • 2 tablespoons of butter
  • 2 tablespoons of flour
  • Salt and pepper to taste


  1. Preheat the oven to 375 degrees F. Lightly grease a 9”x9” casserole dish.
  2. Thinly slice the Roma tomatoes, and slice the zucchini into half-inch slices.
  3. Dice the onion, and set it aside.
  4. Layer the zucchini slices and the tomato slices in the casserole dish, alternating between the two.
  5. In a saucepan over medium heat, melt the butter until it starts to bubble. Add the diced onion, and cook for about 3 minutes, until the onion starts to soften.
  6. Whisk in the flour, and stir constantly for about 1 minute.
  7. Stir in the milk, and cook, stirring every so often, until the mixture thickens.
  8. Mix in the shredded cheese, and continue stirring until all of the cheese has melted.
  9. Season with salt and pepper to taste, if necessary.
  10. Pour this cheese mixture over top of the zucchini and tomatoes in the casserole dish.
  11. Cover the casserole dish with aluminum foil. Bake in the oven for 25 to 30 minutes. Remove the aluminum foil, and return to the oven for another 5 to 10 minutes. Optionally, you can also sprinkle a little extra shredded cheese on top!
  12. Allow the dish to cool for a few minutes before serving.