Onion Parmesan Gratin

Indulge in the creamy, savory perfection of Onion Parmesan Gratin, a comforting dish that transforms humble yellow onions into a show-stopping side or standout vegetarian entrée. This recipe features tender onion rings baked in a luscious Parmesan-infused cream sauce, topped with a golden, crunchy panko breadcrumb crust for an irresistible blend of textures. Enhanced with hints of nutmeg and finished with a sprinkle of fresh parsley, this gratin is rich in flavor yet delightfully balanced. With just 15 minutes of prep time and simple pantry staples like butter, milk, and Parmesan, this dish is both elegant and easy to make. Ideal for holiday dinners or weeknight indulgence, it serves up warmth and decadence in every bite!

Nutriscore Rating: 58/100

Prep Time:15 mins

Cook Time:45 mins

Total Time:60 mins

Servings: 6

Ingredients

• 3 pieces Large yellow onions
• 2 tablespoons Unsalted butter
• 2 tablespoons All-purpose flour
• 1.5 cups Milk
• 0.5 cups Heavy cream
• 1 cup Grated Parmesan cheese
• 1 teaspoon Salt
• 0.5 teaspoon Ground black pepper
• 0.25 teaspoon Ground nutmeg
• 0.5 cup Panko breadcrumbs
• 1 tablespoon Olive oil
• 2 tablespoons Fresh parsley (optional, chopped for garnish)

Directions

Step 1

Preheat your oven to 375°F (190°C).

Step 2

Peel the onions and cut them into 1/2-inch thick slices. Separate into individual rings and set aside.

Step 3

Bring a large pot of water to a boil with a pinch of salt. Add the onion rings to the boiling water and cook for 5 minutes to soften slightly. Drain and set aside to cool.

Step 4

In a medium saucepan, melt the butter over medium heat. Once melted, whisk in the flour and cook for 1 minute to form a roux.

Step 5

Slowly whisk in the milk and heavy cream, making sure there are no lumps. Continue stirring until the mixture begins to thicken, about 3-4 minutes.

Step 6

Remove the saucepan from the heat and stir in 3/4 cup of grated Parmesan cheese, salt, pepper, and nutmeg. Adjust seasoning as needed.

Step 7

Lightly grease a 9x13-inch baking dish with butter or non-stick spray. Spread the blanched onion rings evenly in the dish.

Step 8

Pour the Parmesan cream sauce over the onions, ensuring they are well coated.

Step 9

In a small bowl, mix the breadcrumbs, olive oil, and remaining 1/4 cup of Parmesan cheese until evenly combined.

Step 10

Sprinkle the breadcrumb mixture evenly over the top of the dish.

Step 11

Bake in the preheated oven for 25-30 minutes, or until the top is golden brown and bubbling.

Step 12

Remove from the oven and allow to cool for 5-10 minutes before serving. Garnish with chopped parsley, if desired.

Nutrition Facts

Serving size	1106.9 grams (1106.9g)

Amount per serving	% Daily Value*
Calories	1580

Total Fat 111.70g	143%
Saturated Fat 60.80g	304%
Polyunsaturated Fat 1.60g
Cholesterol 295mg	98%
Sodium 4096mg	178%
Total Carbohydrate 91.90g	33%
Dietary Fiber 9.60g	34%
Total Sugars 40.10g
Protein 54.80g	110%

Vitamin D 161IU	805%
Calcium 1473mg	113%
Iron 3mg	16%
Potassium 1318mg	28%

*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: 63.1%

Protein: 13.8%

Carbs: 23.1%