This Whole Roasted Onion Recipe with Vermouth is unexpected and so delicious! When you slow roast whole onions, they turn from raw, firm and sharp to sweet, soft, and aromatic. Itβs day 8 in the hospital for my dad, in the ICU. Hence my absence since the Greek Lasagna, when I told you he was just wheeled into surgery.
Since Iβm filling you in on this, you should know that my dad is a guy who, until recently, at age 80, was still hiking miles at a time, often while carrying his huge, heavy camera equipment in case he saw a new wildflower or bird. Heβs been an avid hiker and photographer since the 1970’s.
Not only has he hiked all of the trails in the Santa Monica Mountains, but heβs helped build many of them, too! My dad has always led a healthy lifestyle, been super fit and incredibly active — which I think will help him through this.
Inspiration for Whole Roasted Onion Recipe with Vermouth
I’m always comforted by cooking — especially with onions because of my mom’s love for them. So here I am with this new delicious Whole Roasted Onion Recipe with Vermouth.
This fresh oregano just looked so pretty sitting under the window in my kitchen in the natural light — I had to capture it before it went into the whole roasted onions.
What’s in the Whole Roasted Onion Recipe with Vermouth?
There are just a few, lovely and simple ingredients in this and that’s part of what makes it so amazing.
- onions
- rosemary
- oregano
- extra virgin olive oil
- butter
- vermouth
How to Make Whole Roasted Onions
Slice about 1/2-inch off from the root end of each onion and about 1-inch off the tip end of each one.Use a knife to mark an βXβ on top, going in only 1/2-inch or so.
Drizzle with olive oil and sprinkle with salt and pepper. Bake, uncovered for an hour. Then remove them from the oven and drizzle with more olive oil, and the vermouth divided among them. Cover and bake for 1 more hour.
Remove from the oven, add fresh herb sprigs, drizzle with a bit more oil and add butter. Bake for another thirty minutes. Let the onions cool in the pan, and then take off the skins, slice and serve with the remaining fresh herbs.
This was the perfect therapeutic recipe to help me feel better, and let me tell you, the result is fit for a party!
If youβve ever roasted garlic before and think itβs delicious, youβll flip over these onions! Meanwhile, your house will have the scent of the fresh oregano, rosemary and caramelized onions, running through it. Win-win!
What does slow roasting onions do to them?
Roasting them for a long time softens them and brings their sugars to the surface. They become almost spreadable!
The addition of fresh herbs makes the onions incredibly aromatic β every bite is laced with the oregano and rosemary and the splash of vermouth. Oh, and letβs not forget the final touch β a little bit of melting butter. Oh my!
Recipes with Vermouth in them are especially flavorful because Vermouth, a fortified wine, is one that’s infused with herbs, barks and other botanicals.
More recipes with Vermouth:
- Skillet Sweet Potato Chicken
- Smoky Chipotle Pumpkin-Sage Risotto Recipe
- Rosemary Honey Turkey Meatballs
- Best Vegetarian Enchilada Recipe Ever!
Yep, I guess I have a thing for recipes with Vermouth. π You might too, after making this Whole Roasted Onion recipe with it.
How to Serve Them
- These whole roasted onions can be served on their own as a side dish β and would be fantastic with lamb or steak. You can also add them to a taco, burrito or a salad.
- I had them for breakfast mixed into scrambled eggs. Delicious!
- Really, you could even just bite into one and be happy. Yes, like an apple!
I hope you enjoy making this recipe as much as I did — whether it cheers you up on a day you’re down, like it did for me, or any day, for a most delicious onion! π

This Whole Roasted Onion Recipe with Vermouth is unexpected and so delicious! When you slow roast whole onions, they turn from raw, firm and sharp to sweet, soft, and aromatic.
*Makes 6 whole onions
*Once the onions are roasted, they will keep for a week or so, wrapped tightly in the refrigerator and can be added to all sorts of dishes, as noted above.
- 6 large yellow onions (about 3/4 to 1-pound each)
- 1/2 cup extra virgin olive oil
- 3 tablespoons extra dry vermouth
- a few sprigs fresh rosemary, washed & dried
- a few sprigs fresh oregano, washed & dried
- 3 tablespoons unsalted butter
- salt and freshly ground black pepper
-
Preheat the oven to 300Β°F, and adjust a rack to the center.
-
Do not peel the onions! Slice the root end off of each one, just about 1/2-inch β only enough to create a base so the onions donβt roll around. Then slice about 1-inch off the tip end of each one, and use the knife to mark an βXβ on top, going in only 1/2-inch or so. Place them in a 9 x 13 x 2-inch pan, root ends down.
-
Drizzle the onions evenly with about 2 tablespoons of the oil and sprinkle generously with salt and pepper.
-
Place in the preheated 300Β°F oven, uncovered. After 1 hour, remove them from the oven and drizzle with another 2 tablespoons of the oil, and the vermouth divided among them. Then cover the pan lightly with foil, return them to the oven for 1 more hour.
-
Remove from the oven again and take off the foil. Add about half of the fresh herb sprigs to the pan, surrounding the onions. Then drizzle the onions evenly with the remaining oil and insert about 1/2 tablespoon of butter into the center of each onion and turn the oven up to 350Β°F. Return the onions, uncovered, to the preheated 350Β°F oven and roast for another 30 minutes.
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Remove from the oven and let them cool in the pan. Once theyβre cool enough to touch, take off the skins, slice and serve with the remaining fresh herbs.
- If at any point while the onions are uncovered, they seem like they are becoming too dark (darker than golden), light cover them again with foil.
- Cooking times may vary, depending on the size of the onions -- just be sure they're very, very soft when they're done.
flgirl says
I’m so excited to try these!!! Can you recommend a substitution for Vermouth? I don’t have any on hand and want to make them tonight. Thanks!
valentina says
Hi! You could also use sherry (cream or dry) — will be sweeter with cream. I think it would lovely. OR, you can skip it all together, and they’ll still be delicious! Enjoy!
Eunice Walach says
Your are a beautiful person whose love for her dad is so special I myself was the daughter to the best man ever MY DAD, I live to cook and was thrilled when I read your story and saw your recipe. I am so anxious to begin this dish.Please never leave me out of any of your posts or recipes Love Eu Springhill FL
valentina says
Hi Eunice, This is such a sweet note. THANK YOU! I’m happy we connected here. If you haven’t already, be sure to subscribe to my site – on the homepage, just beneath my picture. That way, you’ll always be notified when a new recipe is posted. I hope you enjoy these delicious onions. XO Valentina
Sandy Miller says
Hi Valentina,
So sorry to hear dad is still in the hospital. Give him our love. Once he is home I will make mom and dad a nice meal. I have been making the roasted onions for about 2 weeks now. My recipe had no herbs and the onion was cooked face down…..they were so good I made them 3 days in a row. Yours sound even more delicious. I am going to make Ron and I one to go with tonight’s dinner.
Much love,
Sandy
valentina says
Thank you SO MUCH Sandy! I’d love to hear how you make the onions. I’ve been wanting to try something like this for a while. I think using cream sherry would be delicious also. The herbs are really nice because without chopping them, the just add their scent and subtle flavor. You’re so kind to cook for my parents. What a treat. Much love to you & Ron, Valentina xoxo
Priscilla says
Wonderful to hear that your dad’s doctors feel he will recover. It is definitely a long road and his being physically fit will serve him well. I’m glad you found these roasted onions eased your anxiety. Thinking of you and your family, Valentina ?
valentina says
Thank you so much Priscilla! XOXO
Alice says
Thank you for the yummy recipe , looking forward to making . Sending my best wishes for your Father and your Family .
valentina says
Thank you so much, Alice. I hope you enjoy the recipe, and I really appreciate the well wishes. π
Kaye says
Did not know about your dad! So sorry to hear that it didn’t go easily. I’d love to stop by and say hello. I’ll send you an email. Does it matter too much about the variety of onions?
valentina says
Thank you, Kaye. For the times I’ve listed, the onions should be pretty big, but you can try different varieties. The become quite sweet with this cooking method — so you might not want to use too sweet a variety. I will keep you posted about my dad. XOXO V
David says
I am so sorry your father has had such a hard time, and I know that it’s been tough on you all, too. I am relieved for you all that things are going in the right direction.
The onions sound incredible and I just need to convince Mark they will be sweet and not get be him bad onion breath!!
valentina says
I love it, David. Yes, maybe don’t even tell him they’re onions! π Thanks for the kind words about my dad. xoxo
sippitysup says
I hope your dad is continuing to recover and you’ll all be cooking together soon. GREG
valentina says
Thank you so much, Greg! XOXO
Sara | Belly Rumbles says
My thoughts and prayers are with you regarding your dad. You must be under so much stress at this time, I do hope everything goes well.
Your onions look amazing. It is wonderful how they transform when baked, into a completely different animal!
valentina says
Thank you for the kind thoughts about my dad. Much appreciated. And yes, that’s exactly it — the onions become a different animal. Exactly!
Ashley - Forking Up says
Oh man, onions are my LEAST favorite food, but I do like them caramelized, so maybe I’d like this? The spreadable consistency intrigues me. Perhaps with some brie or soft cheese it’d be good on a crostini!
valentina says
oooh, Ashley, I love that — they’d be lovely with soft cheese. especially when they’re still warm. brilliant. π
Jehan Hale says
I love the flavor of roasted onions, so I can imagine slow roasting them is even better! Will have to try!
valentina says
Hope you enjoy them! π
Bintu - Recipes From A Pantry says
Love the addition of the herbs. Roasting adds so much flavour to vegetables, bet this is fabulous
valentina says
Thank you!
Sandhya Hariharan says
Thank you for sharing such a beautiful recipe.. I have never tried roasting whole onions.. but I can make out how much aromatic they can be with all the herbs.
valentina says
Thank you! Hope you try them! π
Leslie Fried says
These look amazingly delicious! However, in the recipe, there’s no mention on where/when to add the vermouth. You also mention removing the foil when the temp is increased, but there’s no mention of putting any foil on? Hate to try and wing it – wanted your input first! Thanks so much.
valentina says
Hi Leslie, First, my apologies for missing those details! I so appreciate you calling it to my attentions — I’m a one woman show and sometimes these things happen. I’ve edited the recipe to include when to add the vermouth and the foil. Both take place in step 4 of the instructions. Thanks for your patience and I hope you love the onions! ~Valentina