Roasted Onion Gratin with Cheddar and Bacon

Slow-roasted onions in a decadent sauce sprinkled with cheddar and bacon creates an unforgettable gratin.

The moment I laid eyes on this beautiful creation it was crazy love. I wanted to high-tail it to the kitchen and immediately start making it. It spoke out loud and said my name. That doesn’t happen often.

The onions roast with nothing more than olive oil, salt and pepper until their sugars caramelize and they take on a golden color around the edges. They turn strongly sweet while keeping a slightly savory edge to them.

This is an easy way to make caramelized onions without babysitting a pan on top of the stove. Not that I’m against the stove-top method. It’s just time-consuming and I’m a multi-tasker. Hands-free caramelized onions? I’m all over it.

The hot, roasted onions are covered in a decadent béchamel made of heavy cream and wine then baked again. The original recipe calls for Gorgonzola; I swapped it out for white cheddar and bacon. Just a touch of each. Over the top. Like sprinkles on a cake.

A finishing touch to further entice you.

Roasted Onion Gratin w/ Cheddar & Bacon

Rating: 51

Prep Time: 15 minutes

Cook Time: 1 hour, 45 minutes

Total Time: 2 hours

Yield: 4 servings

Roasted Onion Gratin w/ Cheddar & Bacon

Slow-roasted, caramelized onions covered in a decadent sauce sprinkled with cheddar and bacon to create an unforgettable gratin.


2 medium yellow onions, cored and quartered lengthwise
2 tablespoons olive oil
coarse salt and freshly ground black pepper, to taste
2 tablespoons unsalted butter
2 tablespoons flour
1 + 1/2 cups heavy cream
¼ cup dry white wine, optional
a grate (or a pinch) or two of fresh nutmeg
heaping 1/2 cup of sharp white cheddar
2 slices bacon, cooked, crumbled


  1. Heat oven to 350 degrees F. Add onions to an 8x8 (or 10ish by 6ish) deep-sided baking dish Drizzle with oil and massage onions with your hands so they are completely coated. Sprinkle with salt and pepper.
  2. Bake 1 hour, halfway through remove from oven and spoon oil off bottom of pan back over onions, return to oven. Once onions are done remove the pan and turn oven up to 400 degrees F.
  3. Heat butter in a medium saucepan over medium-low heat; add flour and stir until smooth; cook 2 minutes stirring often. Whisk in cream and wine until smooth. Continue whisking about 5 minutes. Season with salt, pepper, and nutmeg.
  4. Pour sauce evenly over onions. Sprinkle with cheddar and bacon. Bake 20-25 minutes until bubbly and golden on top. Let set 5 minutes before serving.


Adapted from Saveur

Copyright ©2013 Cinnamon Spice and Everything Nice by Reeni Pisano All Rights Reserved. No copying or duplication of any content (including photos) without the express written permission from the owner of this website.

Subscribe Here

Enter your email address:

Delivered by FeedBurner



  1. jude says

    Just went to get the few missing ingredients and making this now! :)

    How much cooking time should elapse before I add the sauce?

    • says

      Hi Jude! The onions should roast for about an hour before adding the sauce! Then turn up the heat to 400 and bake for another 20 minutes or so. I’d love to hear back on how they turned out. Thanks and enjoy!

      • jude says

        Insanely delicious. I was a little worried during the sauce stage, but, omg, SO GOOD. Since I have two bacon fanatics in the house, I added more bacon to half the gratin, then drizzled some of the bacon fat over the onions since decadence was clearly the order of the day.

        We ate it from the dish standing up in the kitchen making awed comments of delight in between mouthfuls. I think I might try it with broccoli or something in there, less onion.

        SO good. Bless you.

      • says

        Mmm bacon fat. . . broccoli sounds like a good idea too! Or potatoes. I think even shoe leather might be good in there, haha. Thanks for the rave review Jude!

    • says

      It’s a side dish Eva! It would be perfect alongside steak – or any kind of beef. But really it’s so good you could serve it with just about anything. It will be the star. And steal the show.

  2. says

    This whole dish looks decadent to me and I have to try it! Love every ingredient in it and I know it would be a hit around here. Thanks for the recipe!

Leave a Reply

Your email address will not be published. Required fields are marked *