Red onions halved and roasted over indirect heat until soft and sweet, finished with balsamic vinegar and olive oil. The fire caramelises the natural sugars beautifully.
smokeandsoil.com/recipes/fire-roasted-red-onions-with-balsamic
by L Field
Prep
10 min
Cook
12 min
Total
22 min
Serves
4
Level
Hard
Method
BBQ
Ingredients
High heat transforms these vegetables completely. The char isn’t cosmetic — it’s structural, adding bitterness to balance the natural sweetness underneath. Red onions, when cooked over direct fire, develop a depth of flavour that’s hard to replicate in the kitchen. The smoky notes from the grill mingle with the caramelised sugars, creating a harmony that feels both rustic and refined.
This recipe leans on simple, seasonal ingredients — red onions, thyme, a touch of brown sugar and balsamic vinegar — to build layers of flavour without fuss. The balsamic glaze cuts through the richness with a subtle acidity, while the olive oil ensures the onions stay tender and glossy. Cooking over a two-zone fire setup gives you control, allowing you to char and then gently finish the onions, preserving their texture and complexity.
By treating the BBQ as a tool rather than a spectacle, this dish fits seamlessly into everyday cooking. It’s a reminder that good fire-cooking doesn’t need to be complicated or overdone — just thoughtful, clean, and grounded in quality ingredients. Whether served alongside grilled meats or as a standout vegetable on its own, these fire-roasted red onions bring a quiet confidence to the table.
Ingredients
for reduction)
Health Notes
This recipe uses quality, whole ingredients cooked with minimal processing. The grilling method adds flavour without the need for heavy sauces or added fats, making it a relatively straightforward nutritional option.
Notes
Seasonal Variations
Nutrition (per serving, estimate)
320
kcal
28g
protein
6g
carbs
18g
fat
Values are estimates and vary with portion size and preparation.
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Fire Preparation and Setup
Set up the Weber Master-Touch for a two-zone fire configuration. Use a chimney starter to fully ignite the briquettes. Once the coals are ashed over, bank them to one side of the charcoal grate to create a direct heat zone and an indirect heat zone. Place the cooking grate on top. Close the lid, ensuring the top vent is fully open and positioned over the indirect side. Allow the grill to preheat until the dome thermometer registers approximately 180°C (350°F).
Onion Preparation and Seasoning
Trim the top and bottom of each red onion, but ensure the root end remains intact to prevent the layers from separating during the cook. Peel the dry outer skin. Using a sharp knife, score the top of each onion with a cross-hatch pattern, cutting approximately two-thirds of the way down. This scoring allows for deeper penetration of seasoning and facilitates even cooking. Drizzle the onions with the olive oil and season liberally with sea salt and black pepper, ensuring the seasoning penetrates the scored cuts. Place a sprig of thyme into the centre of each scored onion.
Indirect Roasting Phase
Place the seasoned onions directly on the cooking grate over the indirect heat zone. Close the lid. Maintain the dome temperature between 170°C and 190°C (340°F and 375°F), adjusting the bottom vent as necessary. Allow the onions to roast for 40 to 50 minutes. The onions are ready for the next phase when they are significantly softened and the outer layers are beginning to collapse.
Balsamic Reduction
While the onions are roasting, prepare the reduction. Combine the balsamic vinegar and brown sugar (if using) in a small cast-iron pan or heavy-duty foil tray. Place the pan over the indirect heat zone for the last 10 minutes of the onion cook. Allow the mixture to simmer gently until it has reduced by approximately one-third and has a syrupy consistency. Remove from the heat.
Finishing and Glazing
For a desirable char, move the softened onions briefly to the direct heat zone for 3 to 5 minutes, turning frequently. This step is optional but adds a layer of smoky complexity. Once the onions are fully tender and slightly charred, remove them from the grill. Immediately brush the warm balsamic reduction over the scored tops, allowing the syrup to seep into the layers. Serve immediately.
Finishing and Glazing
For a desirable char, move the softened onions briefly to the direct heat zone for 3 to 5 minutes, turning frequently. This step is optional but adds a layer of smoky complexity. Once the onions are fully tender and slightly charred, remove them from the grill. Immediately brush the warm balsamic reduction over the scored tops, allowing the syrup to seep into the layers. Serve immediately.
Health Notes
This recipe uses quality, whole ingredients cooked with minimal processing. The grilling method adds flavour without the need for heavy sauces or added fats, making it a relatively straightforward nutritional option.
Per serving (estimate)
320
kcal
28g
protein
6g
carbs
18g
fat
accessory
A grill basket is an essential accessory for anyone serious about clean, whole-food cooking over fire. It allows you to cook smaller, delicate items like vegetables and fish fillets without losing them through the grates. This means less waste and more control over your cooking, which fits perfectly with the Smoke & Soil ethos of everyday BBQ using homegrown and seasonal ingredients. The basket keeps your food contained while still exposing it to direct heat and smoke, encouraging a lovely char and smoky flavour without the risk of flare-ups or sticking. Using a grill basket is straightforward but requires a bit of care to get the best results. Always oil the basket before placing food inside to prevent sticking, and avoid overcrowding to ensure proper charring rather than steaming. The design encourages even cooking and makes it easy to turn your food gently, preserving its shape and texture. It is ideal for weeknight cooking when you want a quick, no-fuss way to grill vegetables or fish without the mess or hassle of fiddly flipping. Incorporating a grill basket into your BBQ routine also promotes versatility. You can experiment with different vegetables, marinate fish fillets, or even try delicate items like tofu or halloumi. It’s a simple tool that enhances your ability to cook clean, seasonal food over fire, keeping the process efficient and enjoyable. This accessory aligns with our no-nonsense, confident approach to BBQ and fire cooking, making it a must-have for home cooks who value flavour and practicality.
Written by
L Field
