Celebrate the end of summer with this simple tomato gratin topped with parmesan cheese and rosemary.

While everyone’s buying apples by the bushel and (prematurely) breaking out the pumpkin, I’m digging myself out of probably 20 pounds of tomatoes.

It started with my trip to Del Monte’s farms and the delicious Roma tomatoes the Pereira family let us take home and then things just got out of hand when my parents left for a 10 day vacation right in the middle of their garden literally exploding with tomatoes.

At one point I had an entire paper grocery bag filled to the brim with them.

Tomato gratin in a baking dish topped with parmesan cheese.
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Besides eating them straight up with some olive oil and kosher salt and an uncountable amount of simple tomato/basil salads, I’ve made 20 minute tomato sauce, a zucchini ricotta bake, roasted tomato soup, and now this tomato gratin.

This is me embracing my inner Paula Deen.

End of summer garden fresh tomatoes don’t need much to taste delicious, but I can’t say butter doesn’t help.

Paula knows what she’s talking about with that.

We’re not using any type 2 diabetes inducing amounts or anything, but just a bit dotted on top creates such flavor as it melts down into the tomatoes and seeps into the onion base while baking.

And of course, topping with cheese is good. Always good.

I’m making this recipe my final plea to you all to soak up the last bit of summer and enjoy the end of these tomatoes, peaches and squash you’ll be yearning for again come February when the lull of the holidays is over and it’s still frigid outside.

That can of pumpkin isn’t going anywhere but these tomatoes are almost on borrowed time waiting around for that first frost.

Check out the tomato ricotta tart Julie made with her surplus of Roma tomatoes from our Del Monte trip.

Fresh tomato gratin with parmesan cheese in a baking dish on a cutting board.

What I Love About this Tomato Gratin Recipe

  • Easy Summer Side Dish
  • Minimal prep work and cleanup
  • A good way to use up an abundance of tomatoes
  • Made with simple ingredients

Tomato Gratin Ingredients

  • tomatoes – we are going to be slicing the fresh tomatoes, so you can use your favorite variety
  • yellow onion
  • fresh rosemary
  • extra virgin olive oil
  • salt & pepper to taste
  • balsamic vinegar
  • butter
  • freshly grated parmesan cheese
Parmesan Tomato Gratin | runningtothekitchen.com

How to Make the Best Summer Tomato Gratin Recipe

Start by preheating the oven to 425 degrees.

Over medium heat, add the olive oil to a large skillet and saute the onion and rosemary just until they are soft.

Transfer to a baking dish and layer slices of fresh tomatoes on top of the onions.

Dot small amounts of the softened butter on top of the tomatoes then drizzle with the balsamic vinegar. Season with salt and pepper.

Sprinkle the parmesan cheese on top and bake for 15 minutes.

Allow the dish to cool slightly before serving.

Tips and Variations

  • To cut down on cleanup, if you have a large dutch oven or cast iron pan, you can sauté the onions then place everything into the oven by just using a skillet.
  • For a more caprese feel, use mozzarella cheese instead.
  • Have an abundance of summer squash? Add in squash and zucchini. You may need to cook the gratin a little longer. Looking for a winter version? Here’s a delicious golden beet gratin recipe.
  • You can also mix the parmesan cheese in with breadcrumbs for another topping idea.
  • No need to seed the tomatoes before adding them to dish. This actually makes it drier.

What to Serve with Tomato Gratin

This summer gratin would go great with grilled scallops, bbq short ribs, or my favorite cream cheese chicken recipe.

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Parmesan Tomato Gratin

Servings: 4 servings
Prep: 5 minutes
Cook: 15 minutes
Total: 20 minutes
Celebrate the end of summer with this simple tomato gratin topped with parmesan cheese and rosemary.


  • 4 plum tomatoes, sliced (or any variety of ripe tomato)
  • 1 medium yellow onion, chopped
  • 1 tablespoon fresh rosemary, chopped
  • 1 tablespoon extra virgin olive oil
  • salt & pepper to taste
  • 1 tablespoon balsamic vinegar
  • 1 tablespoon butter, softened
  • 1/2 cup freshly grated parmesan cheese


  • Preheat the oven to 425 degrees.
  • Heat a large skillet over medium heat and saute onion, rosemary and olive oil for about 3-5 minutes just until softened.
  • Transfer the onion mixture into a baking dish.
  • Layer the tomato slices on top of the onions.
  • Dot the tomatoes with the softened butter, drizzle with the balsamic vinegar and season with salt & pepper.
  • Layer the parmesan on top and bake for 15 minutes.
  • Let cool for 5 minutes before serving.


Serving: 1SERVINGCalories: 134kcalCarbohydrates: 7gProtein: 5gFat: 10gSaturated Fat: 4gPolyunsaturated Fat: 5gCholesterol: 18mgSodium: 327mgFiber: 1gSugar: 3g

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Side Dishes
Cuisine: American
Founder and Writer at Running to the Kitchen | About

Gina Matsoukas is an AP syndicated writer. She is the founder, photographer and recipe developer of Running to the Kitchen — a food website focused on providing healthy, wholesome recipes using fresh and seasonal ingredients. Her work has been featured in numerous media outlets both digital and print, including MSN, Huffington post, Buzzfeed, Women’s Health and Food Network.

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  1. Prematurely breaking out the pumpkin–HA! I heart you. I started seeing pumpkin recipes in August and I was like “Whaaaaa???” It is definitely still tomato season and this looks like the perfect way to use them!

  2. this looks so freaking good. i love that you used tomatoes to make a gratin instead of the regular ‘ol potatoes. i bet it was exceptionally good cause of the fresh, ripe tomatoes we got!! :)

  3. I am totally on the hang-onto-the-last-bits-of-Summer train too! I love the simplicity of this gratin. It may even get my cooked tomato hating hubby to like cooked tomatoes! Looks delishhhh.