Potato Gratin

Colorful and wonderfully savory, this potato gratin is a vibrant mosaic of a variety of potatoes and delicious veggies, making for a delectable side dish or even a complete vegetarian meal. Filled with a combination of sweet potatoes, red potatoes, gold potatoes and purple potatoes, plus yellow squash, zucchini, Roma tomatoes and a topping of four cheeses, this potato gratin recipe is extra warming and cozy on a chilly evening!

A Colorful Mosaic of a Gratin

There are so many occasions when the beautiful colors of the season inspire a recipe…

Take for instance this vibrant potato gratin, which is my deliciously edible take on the golden-hued sunsets of the fall season that are mingled with golds, purples and pinks.

This rich and lovely potato dish is ideal to be served as a mouthwatering side, or even a fantastic main dish fit for a “meatless Monday” to be enjoyed with thick slices of warm bread and perhaps a little glass of wine on the side.

This rustic, casserole-style gratin is prepared very simply with a combination of sliced sweet potatoes, purple potatoes, red potatoes and gold potatoes, but of course, there's more…

My recipe has yellow squash and zucchini tucked in between the layers of potatoes, plus juicy slices of Roma tomatoes and a finishing topping of a pungent four-cheese blend melted over top, with all of these ingredients nestled onto a bed of caramelized onions.

The finished gratin is tender, sweet and savory, herby, earthy, and wonderfully juicy—perfect for sopping up with that warm bread to warm the belly!

My Potato Gratin with Lots of Colorful Veggies

Potatoes are an ingredient which I often cook with, and what I adore about them is the variety of colors and flavors that are available to us. So when I can make an entire dish using a combination of colorful potatoes, it’s a real treat for me!

This potato gratin was a recipe that I created when I happened to have a handful of a variety of potatoes on hand—some sweet potatoes, a couple of red and yellow waxy potatoes, plus some purple potatoes—and decided to turn them into a hearty dish that I could either serve as a side, or as a casserole that could be enjoyed as a vegetarian main dish.

And to give this gratin extra texture and flavor, I added some extra vegetables with slices of zucchini and squash, juicy tomatoes, plus a bottom layer of caramelized onions for sweet-savoriness.

And of course, a sprinkle of cheese could only enhance all of this, so a finishing sprinkle of an ooey-gooey cheese blend to melt over top of it all makes things extra cozy and irresistible.

Here's a peek at my potato gratin recipe: (or just jump to the full recipe...)

1. To get started, I caramelize my onions to have those ready to add to the bottom of my casserole dish.
2. Once the onions are caramelized and I add them to the bottom of my dish, I assemble my potato gratin by alternating the colorful potato slices over top of the onions (sort of in the look of fish scales, overlapping slightly), then nestle in between those my zucchini and yellow squash circles.
3. Next, I add my Roma tomato slices over top, plus my herbs and seasoning,
4. When all my ingredients are layered in, I cover the dish with foil, then bake the potato gratin for about 1 hour.
5. After an hour, I remove the foil and sprinkle on the cheese, then bake, uncovered, for an additional 20 minutes until the cheese is golden and melted, and the potatoes fork tender.

Recipe

Potato Gratin

by Ingrid Beer

Print Recipe

This potato gratin is filled with colorful potatoes, caramelized onions, zucchini, squash, tomatoes and thyme, plus a four cheese topping!

Category: Entree
Cuisine: American

Yield: Serves 6

Nutrition Info: 343 calories per serving

Prep Time: 20 minutes
Cook time: 1 hour 25 minutes
Total time: 1 hour 45 minutes

Ingredients:

• Olive oil
• 2 large sweet onions, sliced in thin semi-circle slices
• Salt
• Black pepper
• 1 large sweet potato, skin-on, and sliced to ¼ inch thick circles
• 3 large red-skin potatoes, skin-on, and sliced into ¼ to ½ inch thick circles
• 3 large gold potatoes, skin-on, and sliced into ¼ to ½ inch thick circles
• 3 large purple potatoes, skin-on, and sliced into ¼ to ½ inch thick circles
• 1 zucchini, sliced into ¼ to ½ inch thick circles
• 1 yellow squash, sliced into ¼ to ½ inch thick circles
• ½ teaspoon paprika, plus a pinch
• ¼ teaspoon granulated garlic, plus a pinch
• 3 Roma tomatoes, sliced into ¼ to ½ inch thick circles (make about 12 slices)
• 1 tablespoon fresh thyme leaves, divided use
• 2 cups shredded four cheese blend, or other meltable cheese

Preparation:

1. Begin by gathering and prepping all of the ingredients according to the ingredient list above to have ready and organized for use.
2. Preheat the oven to 400 degrees, and line a baking sheet with foil. Have a 12 by 9 by 2 inch deep casserole or baking dish on hand.
3. Begin by placing a large, non-stick pan over medium-high heat, and add about 2 tablespoons worth of olive oil to it. Once the oil is hot, add the sliced sweet onion in along with a good pinch of salt and black pepper, and caramelize the onions for a few minutes until light, golden-brown. Once lightly caramelized, turn the heat off.
4. Next, drizzle the bottom of the baking/casserole dish with about 1 tablespoon worth of olive oil, and add the caramelized onions to the bottom of the dish, creating an even layer of the onions. Then, begin adding the sweet potato, red-skin potato, gold potato and purple potato slices to the dish, alternating the colors as best as possible. Do this so that they’re slightly overlapping and not flat on top of the onions, but layered and sort of resembling fish-scales. Continue until all potato slices are used up, and the dish is filled.
5. Once all of the potato slices are layered into the baking dish, begin adding the zucchini and yellow squash circles into the dish, squeezing them in between the potato slices, here and there, to create some color. Once all of the zucchini/squash circles are layered in, sprinkle over another pinch of salt and black pepper, along with the ½ teaspoon of the paprika and the ¼ teaspoon of the granulated garlic.
6. Next, add the Roma tomato slices over top, and sprinkle on another pinch of sea salt and pepper, plus another pinch of paprika and garlic powder.
7. Cover the baking/casserole dish tightly with foil, place it onto the foil-lined baking sheet, and place into the oven to bake for about 1 hour, or until the potatoes are tender.
8. After about an hour, or once potatoes are tender, remove the baking/casserole dish from the oven and carefully remove the foil. Sprinkle the cheese over top, and place the uncovered baking dish back onto the foil-lined baking sheet and into the oven for another 20 minutes, or until the cheese is golden-brown and melted.
9. Remove the baking/casserole dish from the oven, and sprinkle over top the tablespoon of fresh thyme leaves, and allow the gratin to rest for a few moments, as it will be extremely hot.
10. To serve, use a slotted spoon to scoop up generous portions of the gratin into shallow bowls or onto plates, making sure to get lots of the onions from the bottom, as well as the juices. Season with additional sea salt/pepper is you wish, and serve with warm slices of thick, crusty bread on the side.

Tips & Tidbits for my Potato Gratin recipe:

• A variety of colorful potatoes: This potato gratin is all about autumn colors, and a combo of sweet potatoes, purple potatoes, gold potatoes and red potatoes really creates that rustic look, plus adds some variety when it comes to flavor and texture. But if you cannot find one of the varieties of potatoes, or would simply prefer to use just a couple different types, feel to choose your favorites.
• Extra veggies for lots of juiciness and flavor: The zucchini, yellow squash and tomatoes help to create an abundance of savory juices on the bottom of the potato gratin, which makes bread a tasty addition to this dish to sop up the juices with. You can skip the extra veggies, if you'd like, and only use the caramelized onions and potatoes, then top with cheese at the end. The dish will yield less savory juices, but be quite tasty, nonetheless.
• Four cheese blend, or your favorite meltable cheese: I love to use an Italian four cheese blend to top this potato gratin with, but feel free to use fontina, mozzarella, Gruyere, jack cheese, or any other mild, meltable cheese.

Craving more tasty potato recipes? Check out these Potatoes Au Gratin, these Roasted Potatoes, these Garlic Mashed Potatoes, these Smashed Potatoes with a Crispy Parmesan Crust, or these Cheesy Potatoes!

Cook's Note: This recipe was originally published in 2012, and has been updated with even more love!