I can’t believe that the Canadian Thanksgiving is this weekend already! If you are looking for some side dish recipe ideas for Thanksgiving, or any meal for that matter, these tasty asiago roasted onions are perfect! This is basically an au gratin dish where the veggie is onions rather than the more normal potatoes. You start by slicing some onions into discs, about a 1/4 inch thick, and you lay them down, whole and flat, in a baking dish to pre-roast a bit to tenderize them before pouring on a cream and cheese mixture and sprinkling on even more cheese and roasting it again The onions are roasted until they are so nice and tender and their natural sweetness and pungency nicely complements the creamy cheese sauce for a flavour explosion in your mouth!
These are also great with parmigiano reggiano, aka parmesan roast onions!
This onion gratin is simply fabulous!
Asiago Roasted Onions
Sweet and tender roasted onions in a cream asiago sauce covered in meted cheese!
ingredients
- 4 large yellow onions, peeled and sliced into 1/4 inch slices
- olive oil
- 1/2 teaspoon thyme, chopped
- salt and pepper to taste
- 1 cup of heavy cream
- 2 teaspoons dijon mustard
- 1/2 cup of asiago cheese, grated
directions
- Place the slices of onion in a single layer on the bottom of a greased baking dish, drizzle with oil and season with thyme, salt and pepper before roasting in a preheated 450F/230C oven for 20 minutes.
- Meanwhile, heat the heavy cream in a small sauce pan until it starts to simmer, mix in the mustard and half of the cheese, let the cheese melt pour it over the onions before sprinkling on the remaining cheese.
- Cover in foil and bake for 20 minutes. (The onions will be tender, the cheese melted and the sides bubbling when it is done.)
Option: Replace the asiago cheese with parmigiano reggiano (parmesan), or grana padano cheese, etc.
Onion Gratin
Butternut Squash and Feta Gratin
Potatoes au Gratin
Hot Sweet Onions Dip
Herb Roasted Onions
Onion Chutney
Rutabaga Gratin
Brussels Sprouts with Smoked Bacon, Mustard Cream and a Parmesan Crust
Fennel Gratin
Roasted Cauliflower and Aged White Cheddar Gratin
Creamy Asiago Bacon Wrapped Roasted Onions
Slow Cooker Chipotle Maple Onion Jam
Parmesan Roasted Acorn Squash
This reminds me of your incredible onion gratin (one if my favorite recipes EVER!). Can’t want to try it and have a marvelous Thanksgiving weekend!
Made this last night with fish. Ever better the day after. Love, love, love.
These were absolutely delicious and easy to make. Not sure how you fit that many onions in one baking dish though – I couldn’t even fit two onions in mine. But they were great and I will definitely make these again!
Delicious! This is a great side dish to go with many things. I’m making it tonight as a side dish to a Roasted Garlic Butternut Squash Soup.
So DELICIOUS! Made tonight and such an easy recipe bursting with flavor. I added a half cup more of Asiago Cheese and cooked an additional 5 minutes after removing the foil.
No leftover 🙂
I’m glad you like them!
This looks wonderful. I hope to make it as a side with steaks for a special anniversary/birthday dinner. I’m a little confused, though. Do you cook it in batches? What’s shown couldn’t possibly be four large yellow onions? And do you only use part of the cheese/cream for each batch?
I usually use two large baking pans that fit into the oven at the same time or you could do it in batches. Enjoy!
Kevin,
STOP STOP STOP!!!!
I’m putting on weight!
Will
Thanks so much. This was AWESOME!! This is the the third recipe I have tried from your site. The jalapeño corn fritters and buffalo mushroom poppers were equally as delicious. Can’t decide what to make next!!
I have not made this recipe yet but I will be making the roasted onion. I think this one will make a perfect complement to our Thanksgiving dinner. I’m not the only one who likes onion so most of us to like onions roasted and other dishes so I figured I’d bring this one. Thank you in advance for the fluffy recipe which I will be using.
Enjoy!
Can you use whole white pearl onions? My husband and I loved this recipe! Would like to try it for thanksgiving but with the pearl onions. I’m sure the roasting time will need to be adjusted.
They would be great! Enjoy!
How many pearl onions would I use in place of the 4 large onions? This recipe looks wonderful.
I would go with 4 cups of pearl onions. Enjoy!
I CAN’T TELL IF YOU’VE BAKED THEM TWICE FOR 20 MINUTES (TOTAL OF 40) OR JUST ONE 20 MINUTE BAKE.
THEY SOUND SCRUMPTIOUS.
They are baked for 20 minutes two times, once without the sauce, and then a second time with the sauce. Enjoy!
OOOH MY!!!!!! I used Gruyere because that was what I had—-incredible, such a simple recipe and it is better than others that take a long time to make! Think I need to make a pan of these for Christmas, we are an onion loving family–(my daughter used to pull them out of the garden and eat them like apples.) Thank you for such a great recipe!
nice share, thank you for the post,, I love to read your food receipt.. it’s give me some inspiration how to cook well
This was a delicious dish! A little hint, the leftovers are tasty in a pork tenderloin sammich on a Hawaiian roll with a little bit of Sweet Baby Rays barbecue sauce.
Thank you for sharing!
That does sound like a good use for the leftovers!
How many servings is this? Trying to work out carbs for keto
This makes 4 servings. Enjoy!
I don’t like onions so I didn’t try these, but my husband really likes them a lot and never gets to eat them since I don’t cook them. He LOVED these! I halved the recipe since it was just for him – and he ate it all!!! I did try a taste of the sauce and it was amazing, especially the crispy parts around the perimeter of the pan. Thinking I want to make this again for company or a small holiday gathering.
I’ve been craving onions so I decided to make this tonight. These are so awesome! Like someone else, I did not have Asiago so I used gruyere cheese and this was so, so good. Will definitely make this again. Wished I would of made a double batch. Gave some to my brother & sister-in-law and they both loved it too. A neighbor popped over and gave him an onion to try and he thought they were great. Recipe is a keeper so thank you for sharing it with us. Much appreciated!
These are so good. I didn’t heat or combine the heavy cream and cheese prior to pouring over the onions, and they still turned out excellent. I can tell this is a very forgiving and adaptable recipe. Brainstorming every use for these so I can make them again and again. Excellent as a side dish, and I’m going to try them as a burger topping.
I came back to say again: these are so good! I’ve made them a few times now and my husband just said these would be a $13 side at a fancy steak restaurant.
I must have done something wrong, since I see everyone else had success with this. The amount of sauce wasn’t nearly enough for the amount of onion, and the temperature (450!) was much too high. Smoke was billowing out of my oven.
I’m sorry to hear that you had difficulties! At what point was there smoking? In the first baking or the second baking? Did you sauce coverage look similar to that in the photos?
These were scrumptious !!!!!
Delicious! Made this this afternoon while my daughter and I are sheltering in place together. She’s a vegetarian. We had this and some Parmesan roasted asparagus for a late lunch. The onions were awesome. I made it just as written except I used Herbs de Provence instead of Thyme. Thanks!
These onions are to die for! I make this recipe all the time now and everyone loves it. I am wondering if I could substitute half and half for the heavy cream? I always have to buy the cream for this, whereas I use half and half daily in my coffee so I have it on hand. Thank you for the delicious recipe.
I will answer my own question 😂. I tried using half and half instead of heavy cream….. definitely not as tasty. I will buy the heavy cream from now on. Delicious recipe.
Is the nutritional info for the entire recipe or one serving? thank you
The nutritional info is per serving. Note: I updated the info. (The automatic tool that I use seems to have trouble with cheese by volume rather than by weight.)
thanks for sharing!
thanks for sharing! …
I think this one will make a perfect complement to our Thanksgiving dinner. I’m not the only one who likes onion so most of us to like onions roasted and other dishes so I figured I’d bring this one.
Can I put them into well-oiled muffin tins. One thick slice at a time – to keep their shape?
That will work!
These were absolutely delicious. Everyone loved them and asked me to bring them to Easter dinner. Also very easy recipe to follow.
Yikes!! I cut up four (regulars size) onions and they take up two baking sheets. Is that normal?