Potato, Spinach, and Tomato Gratin is a cheesy baked side dish made with tender potatoes, fresh spinach, and tomatoes. It’s quick and easy to put together and makes a welcome change from the usual rotation.
If you’re like me, sometimes the hardest part of meal planning is coming up with interesting side dishes. I can get the entree – no problem! But the sides sometimes stump me. Especially if you’re serving little ones whose faces don’t always brighten at the prospect of “eating their vegetables.”
Even with the pickiest eaters, the one side you can almost always depend on is potatoes, isn’t it? Really, how many people do you know who don’t like potatoes? I can’t think of one.
To make this recipe as simple as possible, I use convenient refrigerated sliced potatoes and layer them with fresh spinach, tomatoes, and cheddar cheese to make a very kid-friendly side dish. With all that cheese and potatoes, the kids will hardly know you sneaked in a whole bunch of nutritious spinach 😊
What You’ll Like About This Recipe
- It combines simple, familiar ingredients in a way that feels a little unexpected.
- The gratin bakes up with golden edges and a cheesy top that makes it hard to resist.
- It’s quick enough for a weeknight but still feels special enough to serve alongside a roast or holiday ham.
- The spinach and tomatoes add color and brightness, making it look as good as it tastes.
Ingredient Notes
This post may contain affiliate links. Lana’s Cooking is reader-supported and earns a tiny commission at no extra cost to you when you shop from our links.
- Potatoes — Make the prep really easy by using refrigerated pre-sliced potatoes (like Simply Potatoes slices). Or use about 20 ounces of russet potatoes. You’ll need to peel and thinly slice those.
- Spinach — Fresh spinach works best, either regular or “baby” spinach.
- Tomatoes — I highly recommend Roma tomatoes for this recipe. They’re ideal due to their firm texture and lower moisture content.
- Cheddar Cheese — Its nice, sharp flavor really complements the vegetables.
- Green Onions — Add a mild onion flavor and another pop of color.
The complete ingredient list with detailed measurements is included in the printable recipe card at the bottom of this post.
How to Make Potato Spinach and Tomato Gratin
- Preheat the oven to 350 degrees.
- Drizzle the bottom of a baking dish with the olive oil.
- Place half the potato slices in an even layer in the dish. Lightly sprinkle with salt and pepper.
- Layer half the tomato slices on top of the potatoes. Sprinkle with half the oregano.
- Over the tomatoes, scatter half the green onions.
- Add all the spinach as the next layer. Lightly sprinkle with salt and pepper.
- Cover the spinach layer evenly with half the grated cheddar cheese.
- Repeat layers with remaining potatoes, tomatoes, onions, and cheese.
- Cover with foil and bake for 40 minutes.
- Remove the foil and top with the grated Parmesan cheese. Return the dish to the oven and bake for an additional 10 minutes.
- Allow to cool for 5-10 minutes before serving.
Want to save this?
I'll email this post to you, so you can come back to it later!
Recipe Tips
- Using Romato tomatoes will help prevent the gratin from being watery.
- Mix in other cheeses, such as mozzarella or Gruyère, if you like.
- Basil or thyme substitutes nicely in place of oregano.
- To make ahead, assemble the gratin up to a day in advance. Cover and refrigerate until ready to bake. If possible, remove from the fridge and let it come to room temperature before cooking. If baking from cold, add an extra 10-15 minutes to the baking time.
Recipe Variations
- Try adding cooked, crumbled bacon or diced ham between the layers.
- If you like a bit of heat, add a pinch of red pepper flakes when seasoning the potato layers.
- Substitute kale or Swiss chard for the spinach.
Storing and Reheating
- You should store any leftovers in an airtight container in the refrigerator. They’ll keep for up to three days.
- Reheat in a 350°F oven until thoroughly warmed, about 15 to 20 minutes.
Have a question or thought to share?
If you have a question about the recipe or if you’ve made it and want to share how it turned out, I would truly enjoy hearing from you. Just scroll down to leave a comment or add your star rating.
Thank you for stopping by. It means a lot to have you here.
Recipe
Potato Spinach and Tomato Gratin
Ingredients
- 3 tablespoons olive oil
- 20 ounces potatoes recommend: Simply Potatoes Homestyle Slices (or peel and thinly slice Russet potatoes)
- salt
- ground black pepper
- 2 Roma tomatoes sliced approximately 1/4-inch thick
- 2 teaspoons dried oregano
- 4 green onions diced (use all the white and green parts)
- 3 ounces baby spinach uncooked
- 8 ounces sharp cheddar cheese grated
- 1 cup grated Parmesan cheese
Instructions
- Preheat the oven to 350 degrees.
- Drizzle the bottom of a baking dish with the olive oil.3 tablespoons olive oil
- Place half the potatoes slices in an even layer in the dish. Lightly sprinkle with salt and pepper.20 ounces potatoes, salt, ground black pepper
- Layer half the tomato slices on top of the potatoes. Sprinkle with half the oregano.2 Roma tomatoes, 2 teaspoons dried oregano
- Over the tomatoes, scatter half the green onions.4 green onions
- Add all the spinach as the next layer. Lightly sprinkle with salt and pepper.3 ounces baby spinach
- Cover the spinach layer evenly with half the grated cheddar cheese.8 ounces sharp cheddar cheese
- Repeat layers with remaining potatoes, tomatoes, onions, and cheese.
- Cover with foil and bake for 40 minutes.
- Remove the foil and top with the grated Parmesan cheese. Return the dish to the oven and bake for an additional 10 minutes.1 cup grated Parmesan cheese
- Allow to cool for 5-10 minutes before serving.
Notes
- To use frozen spinach, make sure it’s fully thawed and squeezed dry to avoid watering down the dish.
- Roma tomatoes work best here because they don’t release too much liquid while baking.
Nutrition Information
Nutrition information is calculated by software based on the ingredients in each recipe. It is an estimate only and is provided for informational purposes. You should consult your healthcare provider or a registered dietitian if precise nutrition calculations are needed for health reasons.
— This post was originally sponsored by Simply Potatoes and published on October 14, 2014. It has been updated with additional information.
I love a good gratin! Beautiful colors!
Oh my goodness, Lana! This dish look delectable! Love the added spinach!
This is a great gratin. What a nice shortcut using those simply potatoes!
I’m constantly stumped by side dish ideas…so glad I’m not the only one! Main course is no problem for me but I never know what to make on the side. Thanks for the idea!
I had no idea you could get pre-sliced potatoes. Wow, how many easier are gratins now??
Yes! Simply Potatoes has these lovely sliced potatoes and shredded ones for hash browns, too. They’re so convenient to have on hand!
love your casserole dish
This looks WAY easier than that gratins I’ve been making! I definitely need to give this a try. :)
I mean, can you go wrong with anything “gratin”? Looks awesome!
These look delicious!! pinning for later. :)
Lana, this looks super yum and not just for kiddies! I love using the Simply Potatoes and not using my mandolin or shredder. Thanks for this recipe.
Looks delicious. Thank you.
Oh, yes – we love Simply Potatoes. And au gratin potatoes are one of our favorite side dishes (though I can eat it like it’s an entree) – love this spruced up version!
I think this recipe would actually make a very good vegetarian entree, Heather.
Who doesn’t love a good cheesy gratin!
I love that there are potatoes, tomatoes, and spinach in this dish!! And the cheese, too, obviously :)
I find that side dishes often become the star of the meal, outshining the entree. I say we go to meals of all side dishes! This gratin looks wonderful!
I couldn’t agree more, Dara. I often find myself pushing the entree away and taking larger portions of the side dishes!