Creamed Onion Gratin Recipe

This creamed onion gratin is the perfect side dish for any meal! It is so easy to make, and it is absolutely delicious. The onions are cooked in a creamy sauce, and then they are baked in the oven until they are golden brown and bubbly. This dish is sure to please everyone at the table.

Creamed Onion Gratin

Looking for a delicious side dish to make your dinner party stand out? This creamed onion gratin is the perfect way to impress your guests! It’s easy to make and tastes amazing. You can use this as a perfect side or a cheesy starter for any party.

They’ll never guess how simple it is to make this elegant dish. Serve it up with some roasted chicken or beef and watch them rave about your cooking skills.

Want something just as tasty but a little more casual? Make this chili relleno casserole instead!

Ingredients for Onion Gratin

• 2 medium white onions
• 2 medium red onions
• 2 tablespoons olive oil (30ml)
• 2 tablespoons brown sugar (25g)
• 3 tablespoons salted butter (43g)
• 2 tablespoons all-purpose flour (18g)
• 1 cup heavy cream (250ml)
• ¼ cup white wine (60ml)
• ½ cup grated parmesan cheese (45g)
• ½ cup shredded white cheddar (60g)
• ¼ teaspoon ground nutmeg (.5g)
• 1 teaspoon salt (6g)
• ½ teaspoon white pepper (1.25g)

Kitchen Tools Used

• Cutting board
• Chef's knife
• Mandolin slicer or vegetable slicer
• 10" baking dish
• Non-stick skillet
• Wooden spoon
• Measuring cups and spoons

How to Make Creamed Onion Gratin

Video Recipe

Start by preheating the oven to 320°F/160°C and choose a deep baking dish. A 10" oval or 10"x10" is a great choice for this recipe.

Now, you will prepare the onions. I recommend using a mandolin slicer to get even slices, but if you don't have that available, you will simply slice the onions to around ¼" or less thickness. To do this safely, cut the onion in half from root to stem. Then, peel and cut the stem end off. Now, you will slice this carefully into half-onion rings.

Once the onions are ready, place them into the baking dish and drizzle with the olive oil, brown sugar, and a pinch of salt.

Stir this together until the onions are nicely coated, then bake them for 1 hour, stirring every 15 minutes so they caramelize evenly.

Just before the onions are done cooking, begin making the cheese sauce. In a large non-stick skillet, you will melt the butter over medium heat.

Once the butter has melted, whisk in the flour and cook for 1 minute while stirring constantly.

Now, make your roux by whisking in the heavy cream and white wine. Whisk constantly so no lumps form.

Once it is combined and no lumps remain, add in ¼ cup parmesan and ¼ shredded cheddar. Add the nutmeg, and whisk together until the cheese has melted and a thickened sauce has formed.

Remove the onions from the oven and pour the cheese sauce into the baking pan.

Stir to combine and then sprinkle the top with the other ¼ cup each of parmesan and cheddar.

Broil for 1 to 2 minutes, until just browning. Serve immediately with toasted bread.

Chef's Tip

If you are serving this at a party but want to make sure it stays piping warm, use a Crock-Pot casserole slow cooker instead of baking in the oven. It works wonderfully to caramelize the onions, and then can be set on warm to keep the dip hot to serve guests.

Like tips like this? Then check out my latest cookbook, The Complete Cookbook for Beginners. This book is filled with essential skills and step-by-step techniques that are ideal for new home cooks.

What Should I Serve With This Dish?

I love this creamed onion gratin dish because it goes with almost everything. It can be served with any type of protein. I love having it alongside roasted whole chicken or fried chicken wings. It can be served with steak and potatoes or pork and rice. It tastes amazing with pork chops or burgers. You really can't go wrong.

Along with this recipe, you'll want to serve something for dipping. I prefer sliced toasted bread, but below are a few more ideas that pair well for dipping.

• Toasted crostini, baguettes, French bread, or sourdough
• Bagel chips or pita chips
• Tortilla chips or garden vegetable crackers

More Casserole Recipes

This is one of my favorite vegetable dishes because it is so easy to make but seems like it took hours of you slaving over the stove. It's an impressive dish to share. If you want more great vegetable dishes, then below are a few more of our favorites for you to add to your menu plan. Make sure that you bookmark these, print out the recipes, or pin them to Pinterest to make them soon.

• Green Bean Casserole
• Asparagus Casserole
• Cheesy Corn Casserole
• Cauliflower Casserole
• Scalloped Potato Casserole
• String Bean and Mushroom Casserole
• Spinach Casserole

Continue to Content

Yield: 4

Creamed Onion Gratin Recipe

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A delicious creamed onion gratin is the perfect starter or side dish to any entree! Loaded with savory onions and cheese, it's a tasty baked dip!

Prep Time 10 minutes

Cook Time 1 hour

Total Time 1 hour 10 minutes

Ingredients

• 2 medium white onions
• 2 medium red onions
• 2 tablespoons olive oil (30ml)
• 2 tablespoons brown sugar (25g)
• 3 tablespoons salted butter (43g)
• 2 tablespoons all-purpose flour (18g)
• 1 cup heavy cream (250ml)
• ¼ cup white wine (60ml)
• ½ cup grated parmesan cheese, divided (45g)
• ½ cup shredded white cheddar, divided (60g)
• ¼ teaspoon ground nutmeg (.5g)
• 1 teaspoon salt (6g)
• ½ teaspoon white pepper (1.25g)

For serving

• Toasted bread

Instructions

1. Preheat the oven to 320°F/160°C.
2. Peel and cut the onions in half, then slice into thin pieces. ¼" thick or less is best.
3. Place the onions into a 10" baking dish, and then drizzle with the olive oil, brown sugar, and a pinch of salt. Stir together.
4. Bake the onions for 1 hour, stirring them every 15 minutes so they caramelize evenly.
5. In the last 15 minutes of the onions cooking, begin making your cheese sauce. Using a medium to large non-stick skillet over medium heat, melt the butter.
6. Once the butter has melted, whisk in the flour and cook for 1 minute while stirring constantly.
7. Pour in the heavy cream and white wine, whisking constantly, to prevent lumps.
8. Once it is combined and no lumps remain, add in ¼ cup Parmesan and ¼ shredded cheddar. Add the nutmeg, and whisk together until the cheese has melted and a thickened sauce has formed.
9. Remove the onions from the oven and pour the cheese sauce into the baking pan. Stir to combine and then sprinkle the top with the other ¼ cup each of Parmesan and cheddar.
10. Broil for 1 to 2 minutes, until just browning. Serve immediately with toasted bread.

Notes

Substitute the white cheddar with mozzarella, Gruyere, or provolone if desired.

Recommended Products

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  Slitzer Germany 7-Piece Chef's Knife Set, Ergonomically Designed, Professional Grade Chef Knives, Great addition to any kitchen
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  Wood Cutting Board Set - Bamboo Cutting Board with Juice Groove - Kitchen Chopping Board for Meat (Butcher Block) Cheese and Vegetables | Heavy Duty Serving Tray w/Handles (3)

Nutrition Information:

Yield:

4

Serving Size:

1
Amount Per Serving: Calories: 543Total Fat: 46gSaturated Fat: 25gTrans Fat: 1gUnsaturated Fat: 17gCholesterol: 116mgSodium: 944mgCarbohydrates: 22gFiber: 2gSugar: 12gProtein: 11g

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