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5 from 2 votes

Creamed Onion Gratin

Perfectly tender onions baked in a creamy bechamel sauce with white wine, fresh thyme and, grated parmesan cheese. Bubbling, golden brown, creamed onion gratin is a perfect side dish for weeknight dinners or holiday meals!
Prep Time15 mins
Cook Time1 hr
Course: Side Dish
Cuisine: American, French
Servings: 4
Calories: 489kcal


  • 3 medium yellow onions peeled and, cut into 8 pieces
  • ¼ c dry white wine
  • 2 tbsp olive oil
  • 2 tbsp butter
  • 2 tbsp flour
  • 1 c heavy cream
  • 1 c grated parmesan cheese divided
  • 1 clove garlic grated
  • 1 tbsp thyme leaves
  • 1 pinch nutmeg
  • salt and pepper


  • Heat oven to 350°. Toss the onions with the olive oil and a pinch of salt. Place in a medium-sized casserole dish, with a baking tray underneath to catch any drips or spills. Pour the white wine over the onions. Bake for 1 hour or until the onions are completely tender, stirring halfway through.
  • In a small sauce pot melt the butter over medium heat; add the flour, and cook, stirring, until smooth and a pale golden color, about 1 minute. Next, whisk in the cream, half the parmesan cheese, thyme leaves, nutmeg and, grated garlic. Cook, whisking, until thickened, about 5 minutes. Turn off the heat, taste, and season with salt and pepper.
  • Turn on your oven's broiler. Pour the sauce evenly over onions. Sprinkle with the rest of the grated parmesan cheese. Broil until the cheese is melted and golden brown on top, about 2 minutes.


Make-Ahead Instructions:
  • Yes, you can make this recipe up to two days ahead of time. To prep creamed onion gratin follow the first two steps and pour the sauce over the onions. Wrap the entire baking dish in foil then refrigerate. To reheat and finish, preheat the oven to 350, remove the foil and bake for 10 minutes, then broil 1 to 2 minutes until golden brown and bubbling.
Ingredient Substitutions:
  • White Wine: If you prefer to not cook with alcohol you can substitute water with a tsp of champagne vinegar. 
  • Parmesan Cheese: Asiago, Manchego, Gouda or Gruyere 
  • Flour: To make this recipe gluten-free use a gluten-free flour like Cup4Cup.
Copper Gratin Pan | Baking Trays  


Calories: 489kcal | Carbohydrates: 14g | Protein: 12g | Fat: 42g | Saturated Fat: 23g | Cholesterol: 119mg | Sodium: 460mg | Potassium: 218mg | Fiber: 2g | Sugar: 4g | Vitamin A: 1351IU | Vitamin C: 10mg | Calcium: 342mg | Iron: 1mg