Low-carb, keto-friendly vegetarian dinner of pan-roasted balsamic roasted Brussels sprouts and onions topped with two soft boiled eggs. The Brussels sprouts and onions are caramelized for a fabulous umami savory flavor.Jump to Recipe
If you want an easy dinner that takes little planning, is roasted vegetables topped with a poached egg. Like this roasted cauliflower with quinoa crispies. Although, the veggie don't really need to be roasted. These baked potato skins with a poached egg is another favorite. If I have some baby spinach on hand, I put that under the egg.
❤️ Why you'll love this recipe
- Easy with only 6 ingredients (not including salt, pepper and olive oil).
- Great vegetarian main dish thanks to protein from the eggs.
- Brussels sprouts are so nutritious!
🧅 Main Ingredients + Notes
For the all of the ingredients, measurements and directions, go to the Recipe Card at the bottom of this post.
- Red onion
- Brussels sprouts
- Garlic - either garlic cloves or garlic paste in a tube.
- Balsamic vinegar - use a fruity one, if you have it. I used a tangerine infused balsamic vinegar.
- Melty cheese (optional) - such as Monterey Jack.
- Eggs - I always use pastured eggs, which are healthier.
- Celery salt - You may think the final flourish of celery salt is unnecessary, and you would be wrong! Add celery salt to your grocery list, and get the smallest size you can find if you must, but this adds a final layer of flavor that makes a huge difference to the dish.
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🔪 Recommended Equipment
- Medium skillet
- Chef's knife
📝 Instructions Overview
Detailed instructions for making these pan roasted Brussels sprouts with caramelized onions are in the recipe card below, but here's an overview!
Caramelize the onions. It's up to you how caramelized you prefer the onions. I've cooked them to several different points of caramelization, and prefer them a little lighter. If you look below, though, you'll see a much deeper caramelization.
I start them on medium-high, and then lower the heat once I see caramelization beginning.
Sear the Brussels sprout. Toss the Brussels sprouts in balsamic vinegar, and sear them in the same pan you cooked the onions, to the degree of caramelization you want. Above, they're fairly heavily caramelized, versus the photo at the top of the post.
The only difference is how long you cook them.
Finish. Finish the dish with celery salt, kosher salt, and pepper. And top with a couple poached eggs. If you prefer, you can fry them over easy too, or make hard boiled eggs, and just boil them for 10 minutes before removing them and peeling them.
🍳 Shopping, Prepping & Cooking Tips
Before slicing the onions, if your eyes are particularly sensitive to onions, pop them into the freezer for 10 minutes.
When slicing the onions, remove the bottom of the onion, and slice it in half lengthwise. Chop off the top and bottom, and slice the onion into thin lengths, cutting into the onion lengthwise with a sharp chef's knife. Onions lay flatter in a skillet when sliced in this direction instead of across the width.
When purchasing Brussel sprouts, purchase ones still attached to the stalks if possible. They will likely be more fresh than buying them individually.
Prepping Brussels sprouts is easy. Just slice off their bottom nubs, remove any discolored or wilted leaves, and slice in half lengthwise.
⏰ Tips to Simplify and Save Time
- Toss the prepped Brussels sprouts in olive oil and balsamic vinegar, and air fry the Brussels sprouts while the onions cook in the skillet. When done, add them to the onions in the skillet, and sprinkle with celery salt, kosher salt and pepper.
🥩 For the Meat Eaters at the Table
Add a few slices of bacon to the skillet, cut into lardons.
Don't have time to run to the grocery store? Order the ingredients for this recipe using Instacart (affiliate link). Just click on the Instacart button in the recipe card below, and the ingredients will all be organized for you on their site. Plug in your zip code, choose the store you prefer, and select the ingredients you want delivered to your home.
Balsamic Roasted Brussels Sprouts & Onions with Runny Eggs
- Small pot (if poaching eggs)
- 2 cups thinly sliced red onions (1 large red onion)
- 2 tablespoons extra virgin olive oil divided
- 1 teaspoon kosher salt, divided
- ¼ teaspoon black pepper, divided
- 1 pound Brussels sprouts, trimmed and sliced in half
- 1 tablespoon balsamic vinegar
- ¼ teaspoon celery salt, or more to your preference
- 4 large eggs
- Thinly slice the red onion. Look below in the notes for some tips. Slice off the bottoms of the Brussels sprouts, and slice in half.
- Warm 1 tablespoon of the olive oil in a cast iron skillet over medium-high heat. Add the onions, ¼ teaspoon salt and ⅛ teaspoon black pepper. Toss, using tongs, and cook over medium heat until the onions begin to relax. Toss again, and lower the temperature to medium-low. Cook for 10 - 15 minutes, depending on how caramelized you want them. Remove to a bowl.
- Measure the remaining 1 tablespoon of olive oil into the skillet, and add the Brussels sprouts, and the remaining salt and pepper. Toss to coat, and flip all the sprouts over so that their flat sides are in contact with the pan. They might not all fit, but do this with as many of the sprouts as possible. Cook over medium heat without moving them for 8 minutes. They should be well-seared. Check them after 5 minutes to gauge how fast the Brussels sprouts are searing.
- Add the balsamic vinegar. Toss well to coat, and add additional olive oil if the pan is completely dry. Add the onions back to the pan, and cook over medium heat for another 8 - 12 minutes, or until the Brussels sprouts are tender. Sprinkle with celery salt, kosher salt and black pepper to taste.The length of time is also dependent on the size of Brussels sprouts you are cooking.
- While the Brussels sprouts finish cooking, make the eggs if you plan to use them. Either poach, fry or soft boil the eggs. If you opt for soft boiling them, remove the eggs from the boiling water after 8 - 10 minutes, and peel under cold running water.
I seriously need to try this! Looks so good!
The Wimpy Vegetarian
Thanks so much Toni! I hope you do!!! If you try it, let me know how it goes for you 🙂
Now, this is my kind of meal! Although I might make it with a little bacon to start!
The Wimpy Vegetarian
My husband would completely agree with you!! 🙂
Oven temp way too hot at 425. Maybe 390. Burnt those poor babies!
The Wimpy Vegetarian
I'm so sorry those babies burnt! I wonder if being at high altitude (I live and cook at 7100') makes the difference. Either way, I'm going to make them again, and take a look at lowering the temp. I really appreciate the feedback!
This looks great! When do you add the cheese???
The Wimpy Vegetarian
Great catch! Add the cheese in the last 5 minutes in the oven if you use melty cheese like fontina or Gruyere. If the cheese is a little less melty, such as some cheddars, add it in the last 10 minutes in the oven. I'll update the recipe - I appreciate you bringing that to my attention!