Onion Gratin

Elevate the humble onion to a star ingredient with this decadent Onion Gratin recipe, a dish that seamlessly blends rich, caramelized flavors with creamy, cheesy indulgence. Thinly sliced yellow onions are slowly caramelized in butter and olive oil, enhanced with a touch of sugar for a subtle sweetness, and layered with velvety heavy cream. A golden crust of Gruyère, Parmesan, and crispy panko breadcrumbs, infused with fresh thyme, adds the perfect balance of crunch and savoriness. This irresistible gratin is baked to bubbling perfection and garnished with fresh parsley for a pop of color. Ideal as an elegant side dish or a comforting vegetarian centerpiece, this easy-to-make dish is the perfect way to bring warmth and sophistication to your table. Optimized for comfort food lovers and holiday gatherings alike, it’s a recipe you’ll turn to again and again.

Nutriscore Rating: 53/100

Prep Time:15 mins

Cook Time:50 mins

Total Time:65 mins

Servings: 6

Ingredients

• 4 large yellow onions
• 3 tablespoons unsalted butter
• 2 tablespoons olive oil
• 1 teaspoon granulated sugar
• 2 large garlic cloves
• 1 cup heavy cream
• 1 cup grated Gruyère cheese
• 1 cup grated Parmesan cheese
• 1 cup panko breadcrumbs
• 1 teaspoon fresh thyme leaves
• 1 teaspoon salt
• 0.5 teaspoon black pepper
• 2 tablespoons fresh parsley

Directions

Step 1

Preheat your oven to 375°F (190°C).

Step 2

Peel and thinly slice the yellow onions into rings.

Step 3

In a large skillet over medium heat, melt the butter and olive oil together.

Step 4

Add the sliced onions to the skillet and cook, stirring occasionally, for 20 minutes until soft and golden.

Step 5

Sprinkle the granulated sugar over the onions and cook for another 5 minutes to enhance their sweetness.

Step 6

Mince the garlic cloves and add them to the skillet. Stir for 1 minute until fragrant, then remove the skillet from the heat.

Step 7

Lightly grease a baking dish with butter or olive oil. Spread the caramelized onion mixture evenly in the dish.

Step 8

Pour the heavy cream over the onions, ensuring it is evenly distributed.

Step 9

In a bowl, mix the grated Gruyère, grated Parmesan, panko breadcrumbs, fresh thyme, salt, and black pepper.

Step 10

Sprinkle the cheese and breadcrumb mixture evenly over the onions and cream layer.

Step 11

Bake in the preheated oven for 20–25 minutes, or until the top is golden and bubbling.

Step 12

Remove from the oven and let the gratin rest for 5 minutes before serving.

Step 13

Garnish with freshly chopped parsley, and serve warm as a side dish or a standalone meal.

Nutrition Facts

Serving size	1191.5 grams (1191.5g)

Amount per serving	% Daily Value*
Calories	2635

Total Fat 206.40g	265%
Saturated Fat 113.60g	568%
Polyunsaturated Fat 2.70g
Cholesterol 533mg	178%
Sodium 4974mg	216%
Total Carbohydrate 105.90g	39%
Dietary Fiber 13.10g	47%
Total Sugars 33.90g
Protein 79.10g	158%

Vitamin D 24IU	120%
Calcium 2070mg	159%
Iron 5mg	27%
Potassium 1095mg	23%

*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: 71.5%

Protein: 12.2%

Carbs: 16.3%