My Roasted Red Onions are smothered in cream cheese, mustard and chives to really make a feature of a vastly underrated side vegetable. Red onions become soft and sweet when roasted and require minimal effort. Try it, you won’t be disappointed!
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I honestly think that onions are the most underrated vegetable out there. They’re nearly always relegated to being a base flavour. “Start by chopping and softening some onions” says every recipe ever.
Including numerous recipes of mine! But I’m not saying that they should never be used like that. Just that sometimes they deserve to be the star of the show!
And that’s what this recipe for Roasted Onions is all about. The red onions are first roasted with olive oil and salt to soften them and bring out their natural sweetness.
They’re then smothered in a mustard and chive cream cheese mix and baked a little more. The creamy cheese and spiciness of the mustard provide the perfect counterfoil to that sweet onion flavour.
How to Serve Roasted Red Onions
I generally serve one whole onion per serving as a side. For smaller appetites, one half would perhaps be enough.
Make Roasted Red Onions with Creamy Mustard into a Feast
I truly believe that you can make any dish into a proper feast! Whether thats a feast for one after work on a Tuesday, a casual feast for four on a Friday evening or a feast for 12 for a special occasion!
I like to serve my mustard topped onions with roasted meat as part of an alternative style roast dinner. My Paprika & Sage Butter Roast Chicken, Garlic Roasted Sweet Potatoes and Maple Roasted Cherry Tomatoes make up my go-to combo (and features in the photos on this page!
They also make a great side in any of my Americana inspired Feasts.
Ingredients for Roast Red Onions
So I have obviously used red onions and called the recipe “Roasted Red Onions”. There is zero reason that you can’t use white onions. Zero. Nada. They will just turn out a little more brown and a little less purple.
I used wholegrain mustard in my recipe because I like to way that the grains pop when you bite into them. Plus the flavour is nice and subtle. If you prefer the flavour of English or dijon mustard, they could be easily substituted in.
Cream cheese is stable and doesn’t run or split when heated. It is therefore ideal for topping and baking….anything really! But not all cheeses are as stable so whilst you could use mozzarella or cheddar etc, expect a little oil and slippage!
I have used Lighter Cream Cheese in the recipe. This is because I keep the light stuff in my fridge. There would be no problem with using the full fat kind or even a garlic and herb variety for a little extra kick.
Other than using white onions instead of the red, or changing the type of cheese or mustard, you can also vary the flavours in the topping mix. Other fresh herbs like thyme and oregano work especially well.
You could add hot sauce instead of the mustard for a different experience or just keep it simple with plain garlic and chive. Have a look in your cupboard and see what you fancy. Or even better, look what flavours are in with the other dishes you’re serving it with and consider mirroring or complementing those flavours.
Another great option is to add a further crunchy topping like panko breadcrumbs mixed with a little melted butter. Add the buttery crumbs at the same time as the cream cheese mix.
Make it Vegetarian or Vegan
This is a great vegetarian dish and a probable welcome change from a stuffed mushroom! This is especially true if a crunchy breadcrumb topping is added to make a more rounded dish.
These topped roasted onions aren’t quite vegan due to the cream cheese but as there are now numerous dairy free cream cheese options readily available, you can easily make the substitution to make then vegan.
Make it Allergy Friendly
The recipe is gluten, egg and nut free.
Dairy Free: Substitute the cream cheese for a dairy free alternative.
Please note that this recipe may contain other allergens not referred to above. For more information regarding any dietary information provided on this website, please refer to my Nutritional Disclaimer.
Equipment Notes for Roasted Onions
Do make sure to line your roasting tin well. Onion contains sugars which caramelise when cooking. And those caramelised sugars are a real bitch to clean off dishes.
A comprehensive list of the equipment used to make this recipe is included in the main recipe card below. Click on any item to see an example. There are no hard and fast rules so many items can be sensibly substituted to achieve the same results.
My Topped & Roasted Red Onions are quite fragile. Onions are formed of layers and when you cut them, those layers want to fall apart. The situation gets worse when you cook the onions. Moving the cooked onions from one container to another any more times than is nessesary is not ideal.
Despite this, you can absolutely get ahead by doing the initial bake of the onions then storing them in the same dish that they were baked in. I have glass Pyrex dishes with silicone lids which are ideal for this. Covering a roasting tin with foil would work just as well.
You could also make up the topping mix in advance and store that in the fridge for a couple of days. The topping can then be added and the onions baked off just before serving.
I wouldn’t recommend cooking the onions with their topping and then reheating unless wholly necessary. Nor would I recommend freezing the onions at any stage of the process.
Leftover Roasted Red Onions with Cheesy Mustard
I am honestly not a huge fan of cooked then cooled onions being eaten cold. If that is your thing, then leftovers would make a great picnic item. If like me, you only fancy them warm, they are easily reheated in the microwave or oven.
Topped & Roasted Red Onions Tips
Be careful when moving the cooked onions from the cooking dish to the serving plate. The outer rings can fall off very easily!
Don’t be tempted to up the oven temp for a quicker cook. You will just end up with the onions being a little too burnt on the outside and a little to raw on the inside. Not ideal!
Don’t forget to let me know in the comments if you try making this recipe – I want to know what you think and if you made any substitutions, how did it turn out?
Still Have Questions?
Simple! Just contact me and I will do my best to help as quickly as I am able. Head over to my Contact Me page, any of my social media channels or post a comment at the bottom of this page and I’ll see what I can do.
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Roasted Red Onions with Creamy Mustard Topping
- 2 Medium Red Onions
- 2 tbsp Olive Oil
- 2 tbsp Light Cream Cheese
- 2 tbsp Fresh Chives – chopped
- 1 tsp Grain Mustard
- 0.5 tsp Sea Salt Flakes
- Preheat the oven to 200c or equivalent.
- Top, tail, halve (horizontally so you can see the rings) and peel 2 Medium Red Onions.
- Place cut side up in a small roasting tray so that they sit snuggly.
- Drizzle over 2 tbsp Olive Oil and pop in the oven on the bottom shelf for 45 minutes.
- Meanwhile mix together 2 tbsp Light Cream Cheese, 1 tbsp Fresh Chives, 1 tsp Grain Mustard and 0.5 tsp Sea Salt Flakes in a small mixing bowl. Set aside.
- Once the onions have had 45 minutes, take them out the oven and use a small knife to check if they are soft all the way through. Return to the oven if not.
- Once soft, spread the cream cheese mix over the onions. Put the onions back into the oven for 20 minutes.
- Remove from the oven when the onions are golden brown and bubbly on top.
- Serve by basting any oil in the pan over the top of the cream cheese topping and sprinkling them with the remaining 1 tbsp Fresh Chives.