Roasted red onions are sweet, soft, and full of rich, savoury flavour — the kind that only comes from slow cooking. In this recipe, they’re baked until caramelised, then spooned over creamy ricotta and finished with a drizzle of garlic and herb butter. This dish looks impressive, but is very low effort with a great presentation and great taste.
Roasted red onions are a bit of a kitchen secret — they need hardly any attention but come out of the oven tasting like something far more complicated, plus they are really affordable and budget-friendly. Roasting them slowly lets their natural sugars develop, so the flavour becomes soft, slightly sweet, and deeply savoury. I pair them with ricotta here because the creaminess balances the onions perfectly, and that final touch of warm garlic butter with thyme and oregano pulls everything together. This dish works beautifully as a starter, a snack with crackers or bread, or even as part of a grazing board for Christmas or Easter family gatherings!
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Ingredients to Make Roasted Red Onions
Here is what you need to make roasted red onions:
- Red onions – These roast into soft, sweet wedges with crispy edges. They’re the heart of the dish. They are budget-friendly, affordable all year round and have a lot of health benefits.
- Olive oil – Helps everything roast evenly and brings out the flavour of the onions. Extra virgin if you have it.
- Fresh thyme or dried thyme – Adds an earthy, herby base note that pairs beautifully with roasted onions. I like to use fresh thyme in this recipe, because the thyme sprigs looks amazing when you garnish the serving platter with them.
- Dried oregano – A stronger herb that balances the sweetness of the onions.
- Salt and black pepper – Essential for seasoning and enhancing all the flavours.
- Ricotta – Creamy and mild, ricotta is the perfect base for the warm, herby onions. Ricotta itself is very delicate, it is like a canvass for other flavours - so generously sprinkle black pepper and salt on it before the serving.
- Butter – Adds richness to the dish. Use salted if you like, or unsalted with a pinch of salt. Butter is infused with garlic, thyme and oregano; we make this buttery sauce to bring all the flavours together. You can melt butter on the stove in small saucepan, or can you microwave, just heat it in intervals, otherwise it can be overheated, you will end up with cleaning the microwave.
- Garlic – Finely grated so it melts into the butter and infuses everything with warmth.
- Extra herbs – More thyme and oregano to finish the butter. More fresh thyme sprigs to garnish the dish.
- Bread or crackers – You’ll want something sturdy to scoop up every bite. Rustic bread, ciabatta, rye thins — all work well.
If you're up for experimenting, you could swap the ricotta for whipped feta or mascarpone, or try using rosemary instead of thyme for a slightly different flavour. You can spice up ricotta with hot honey and chilli flakes.
Instructions to Make Roasted Red Onions
This is an easy, hands-off recipe that gives you a big reward at the end. Just let the oven do its thing. The one thing - allow onions to cook with lower temperature during the longer time. While, it can be roasted with higher temp for 20-25 minutes, the flavour would not be same. Cooking them longer would bring more sweet caramelisation that pairs wonderful with ricotta.
- Step 1: Preheat your oven to 160°C (320°F). Peel and cut the red onions into wedges, then arrange them on a baking tray. Lining the tray with foil will help with clean-up.
- Step 2: In a bowl, mix the olive oil with thyme leaves, oregano, salt, and pepper.
- Step 3: Pour the oil and herb mixture over the onions and use your hands to rub it in, making sure everything is evenly coated. Add 50 ml of water to the tray, then place in the oven for 1.5 hours. Stir very gently halfway through cooking.
- Step 4: Just before serving, put the butter, grated garlic, dried oregano, chopped thyme, and a bit more black pepper into a microwave-safe bowl. Heat in 30-second bursts until the butter is melted and smells delicious. Spread the ricotta onto a serving plate or tray, season well, top with the roasted onions, and drizzle over the garlic herb butter. Serve immediately with good bread or crackers.
- Tip 1: Roasting low and slow gives the onions time to fully caramelise, bringing out their sweetness without burning.
- Tip 2: Stir halfway through very gently to avoid breaking up the wedges too much — they’re soft but delicate by that stage.
Storage
Roasted red onions are best served warm, just after they’ve come out of the oven and been spooned over ricotta. The contrast between hot onions and cool cheese is part of what makes this dish so good. A drizzle of garlic and herb butter brings it all together, and good bread is a must — something sturdy to scoop up every last bit. If you're making this for guests, assemble just before serving so everything stays fresh. If you have leftovers, they’ll keep well in the fridge for up to three days. Store the onions and ricotta separately if possible, and reheat the onions gently in a low oven before serving again. You can also freeze the onions — just defrost in the fridge overnight and warm them up before using.
Top Tips to Make This Dish Even Better
- Cutting the onions into wedges allows them to cook evenly and hold their shape. You don’t have to stress if some wedges fall apart — that’s completely normal. The thinner layers tend to crisp up a bit more, which gives a lovely mix of textures. Just try to keep the wedges fairly even in size so they roast at the same pace. If any pieces burn too quickly, tuck them into the centre of the tray.
- Adding a little water to the baking tray at the start helps the onions cook gently at first. This steam prevents them from drying out or catching on the tray before they begin to caramelise. As the water evaporates, the onions slowly start to roast and sweeten. Without the added water, you might find the roasted red onions cook too quickly on the outside while staying raw inside.
- Thyme and oregano give the onions a really nice, savoury background. Fresh thyme adds a subtle, almost lemony note, while dried oregano has a stronger, slightly bitter edge that cuts through the sweetness. You can adjust the amounts to suit your taste. If you’re not a fan of oregano, rosemary or marjoram are good alternatives.
- Roasting at 160°C for 90 minutes gives the best texture and flavour. It might feel like a long time, but this is what transforms the onions. They go soft and sweet inside, with caramelised edges that aren’t too dry or burnt. If you rush the cooking at a higher temperature, you’ll miss out on that depth of flavour and texture.
- Ricotta is a mild cheese, so don’t forget to season it well before serving. A little salt and pepper (or even some lemon zest if you want extra freshness) makes a big difference. You could also try blending the ricotta with a splash of olive oil or cream if you prefer a looser, whipped texture.
- This dish is very flexible — you can easily change it up. If you don’t have ricotta, try whipped feta or mascarpone. If you want to add more herbs, go for it — sage, rosemary, or even a bit of parsley would all work. You could also sprinkle toasted nuts or seeds over the top for extra crunch.
- Assemble everything just before serving for the best result. The roasted red onions are nicest when they’re warm and soft, and the butter should still be melted when you pour it over. If you leave it sitting too long, the butter can harden and the ricotta can get watery. Prep ahead, but combine everything at the last minute.
FAQ
Can I use yellow or white onions instead of red?
Yes, but red onions are naturally sweeter and give a better flavour when roasted. Yellow onions tend to have a sharper bite and need more time to mellow out. If you use them, consider adding a splash of balsamic vinegar to balance the flavour.
Can I make roasted red onions ahead of time?
Definitely. You can roast them a day ahead and store them in the fridge. When you’re ready to serve, just warm them in the oven and assemble the dish fresh. The ricotta and garlic butter are also quick to prep last-minute.
Can I make this dish vegan?
Yes, very easily. Swap the butter for a plant-based version and use a dairy-free cheese instead of ricotta. Something like almond or cashew-based spread would work well here.
Can I freeze roasted red onions?
Yes — let them cool completely, then store in an airtight container or freezer bag. Defrost in the fridge overnight and reheat gently in the oven. The texture might change slightly, but they’ll still taste great.
Why add water to the baking tray?
It helps start the cooking gently by creating steam. This stops the onions from drying out too fast and lets them soften before the caramelisation kicks in. It’s a small step, but it really improves the final texture.
Related
Looking for other recipes like this? Try these:
- Salmon Spinach Salad Recipe
- Five Spice Chicken Wings Recipe
- Parsnip Fritters Recipe
- Roasted Cherry Tomatoes
Roasted Red Onions
Roasted red onions are slow-baked until soft, sweet, and caramelised. Served over creamy ricotta with warm garlic herb butter, they’re perfect with rustic bread or crackers.
Ingredients
- 6 red onions, cut into wedges
- 4 tablespoon olive oil
- 5–6 thyme sprigs, leaves picked (or 1 tablespoon dried thyme)
- 1 tablespoon dried oregano
- Salt and black pepper
- 300 g ricotta
- 3 garlic cloves, finely grated
- 50 g salted butter, cubed
- ½ teaspoon dried oregano
- More thyme sprigs
- Crackers or rustic bread
- Freshly ground black pepper
Instructions
- Preheat the oven to 160°C (320°F). Peel and cut the onions into wedges. Place on a foil-lined baking tray.
In a bowl, mix olive oil, thyme, oregano, salt, and pepper. Pour over the onions and rub everything in with your hands. - Add 50 ml water to the tray. Roast for 1.5 hours, stirring gently halfway through.
- In a microwaveable bowl, combine butter, garlic, thyme, oregano, and pepper. Heat in 30-second bursts until melted and fragrant.
- Spread ricotta on a plate, season, top with roasted onions, and drizzle over the garlic butter. Serve immediately with crackers or bread.
Notes
Roasting low and slow gives the onions time to caramelise and soften properly.
Don’t worry if the wedges break apart during cooking — the smaller pieces are often the tastiest.
Water in the tray helps the onions steam before they roast.
Use salted butter for better flavour, or unsalted with an extra pinch of salt.
Always serve immediately after assembly for best flavour and texture.
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