Potato Gratin with Caramelized Onions

Indulge in the ultimate comfort food with this Potato Gratin with Caramelized Onions recipe—a luxurious side dish that’s sure to elevate any meal. Perfectly sliced Yukon Gold potatoes are layered with rich caramelized onions, creamy garlic-infused sauce, and a decadent blend of Gruyère and Parmesan cheeses. The addition of fresh thyme enhances the flavor, creating an irresistible medley of creaminess and savory sweetness in every bite. Finished with a golden, cheesy crust, this gratin is a show-stopping dish that’s as impressive for holiday feasts as it is for weeknight dinners. Easy to make ahead and perfectly satisfying, this recipe is destined to become a family favorite.

Nutriscore Rating: 60/100

Prep Time:25 mins

Cook Time:75 mins

Total Time:100 mins

Servings: 6

Ingredients

• 6 medium Yukon Gold potatoes
• 2 large Yellow onions
• 4 tablespoons Unsalted butter
• 2 cups Heavy cream
• 1 cup Whole milk
• 3 minced Garlic cloves
• 2 cups (shredded) Gruyère cheese
• 1 cup (grated) Parmesan cheese
• 1.5 teaspoons Salt
• 1 teaspoon Black pepper
• 1 teaspoon Fresh thyme leaves
• 1 tablespoon Olive oil

Directions

Step 1

Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with butter or non-stick cooking spray.

Step 2

Peel the potatoes and slice them into very thin rounds, approximately 1/8-inch thick. Use a mandoline slicer for best results.

Step 3

Peel and slice the onions into thin rings.

Step 4

In a large skillet over medium heat, add 1 tablespoon of olive oil and 2 tablespoons of butter. Once melted, add the sliced onions, a pinch of salt, and cook for 25-30 minutes, stirring occasionally, until they are golden brown and caramelized. Set aside.

Step 5

In a medium saucepan, heat the remaining 2 tablespoons of butter over medium heat. Add the minced garlic and sauté for 1 minute until fragrant.

Step 6

Pour in the heavy cream and milk, then stir in the salt, black pepper, and thyme. Heat the mixture gently, but do not let it boil. Remove from heat.

Step 7

Spread a thin layer of the cream mixture at the bottom of the prepared baking dish. Begin layering by adding a layer of potato slices, slightly overlapping them. Sprinkle a portion of the caramelized onions over the potatoes, followed by a handful of Gruyère cheese.

Step 8

Repeat the layering process (cream mixture, potatoes, onions, Gruyère) until all the ingredients are used up, finishing with a top layer of potatoes.

Step 9

Pour the remaining cream mixture evenly over the top layer of potatoes. Sprinkle the Parmesan cheese over the top to create a crispy, golden crust.

Step 10

Cover the baking dish with aluminum foil and bake in the preheated oven for 45 minutes. Then, remove the foil and bake for an additional 25-30 minutes, or until the top is golden brown and the potatoes are tender when pierced with a knife.

Step 11

Let the gratin cool for 10 minutes before serving. Garnish with additional thyme leaves if desired and enjoy!

Nutrition Facts

Serving size	(2678.8g)

Amount per serving	% Daily Value*
Calories	4797.7

Total Fat 344.8g	0%
Saturated Fat 198.6g	0%
Polyunsaturated Fat 6.2g
Cholesterol 1012.6mg	0%
Sodium 6422.0mg	0%
Total Carbohydrate 259.6g	0%
Dietary Fiber 22.3g	0%
Total Sugars 33.6g
Protein 147.6g	0%

Vitamin D 170.7IU	0%
Calcium 4123.6mg	0%
Iron 10.9mg	0%
Potassium 6124.9mg	0%

*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Source of Calories

Fat: 65.6%

Protein: 12.5%

Carbs: 21.9%