Roasted Red Onions

Ingredients

• 2red onions
• 30 ml (2 tablespoons)olive oil or coconut oil
• to tastekosher salt and pepper

Instructions

1. 1

   Heat the oven

   Preheat the oven to 204°C (400°F). Line a rimmed baking sheet with parchment paper, or brush it lightly with oil.

2. 2

   Slice and season

   Cut the onions into 1.3 cm (½-inch) slices and arrange them on the baking sheet. Brush lightly with oil, then season with salt and pepper.

3. 3

   Roast until tender

   Roast for 15–20 minutes, turning the onions once halfway through, until tender and caramelised.

What are roasted red onions?

Roasted red onions are a simple American-style side made by cooking sliced onions in a hot oven until they soften and develop browned edges. Roasting brings out their natural sweetness and softens their sharper flavour.

This version keeps the seasoning simple, so the mellow onion flavour works alongside everything from steak to a grain bowl.

Nutrition and macros by portion

The nutrition label shows one serving as written: 83 calories, 0g protein, 0g carbs, 0g fat.

The onions provide most of the carbohydrates, while the oil supplies most of the fat and calories; protein is minimal. For a more filling plate, serve a portion with a protein-rich main and vegetables or grains. The supplied nutrition figures list 0 g for protein, carbohydrate and fat, so treat those macro values as reported rather than a full ingredient-based breakdown.

Choosing the oil

Olive oil: Its savoury flavour suits the onions and helps the surfaces brown as they roast.

Coconut oil: This is the alternative listed in the recipe; use it in the same amount and brush it over the slices lightly.

Slice for even cooking

Even slices: Cut the onions about 1.3 cm thick so they cook at a similar pace. Much thinner slices can soften quickly, while thicker pieces may need more time.

Keep the rings together: Arrange the slices in a single layer on the tray, taking care not to break them up more than necessary.

Turn halfway through

Midway flip: Turn the slices once during roasting so both sides have contact with the hot tray and can colour.

Doneness: The onions are ready when they feel tender and show caramelised patches. If they are still firm, give them a little more time and check again.

Serve them with

For a main meal: Pair the onions with steak or burgers, or spoon them over a grain bowl for a sweet, savoury topping.

As a side: Serve them warm alongside a weeknight meal. Their mellow flavour also complements other simply seasoned dishes.

Make-ahead timing

The onions take 15–20 minutes to roast, so they can be made while the rest of dinner is coming together. Watch for tenderness and browning rather than relying on colour alone.

They can also be roasted ahead and refrigerated for later in the week; reheat gently before serving.

Recipe notes & tips

• Use a rimmed baking sheet to keep the onion slices contained.
• Brush the oil on lightly so the slices are coated without pooling.
• Arrange the onions in a single layer to encourage browning.
• Turn the slices once halfway through roasting.
• Check for tenderness as well as caramelised colour before taking the tray out.

Variations

• Add herbs: Scatter a little chopped thyme over the onions before roasting.
• Add balsamic: Drizzle a small amount over the cooked onions for a tangy finish.
• Use a spice: Dust the slices with smoked paprika before they go into the oven.
• Add garlic: Roast the onions with a little minced garlic for a more savoury flavour.
• Finish with parsley: Sprinkle chopped parsley over the onions just before serving.

Common mistakes to avoid

• Uneven slices: Cut the onions to a similar thickness so they soften at the same rate.
• Crowded tray: Spread the slices into a single layer so they roast rather than steam.
• Too much oil: Brush on a light coating to avoid greasy onions.
• Skipping the turn: Flip the slices once halfway through for more even browning.
• Relying only on the timer: Check that the onions are tender and caramelised before serving.

How to store

Cool the onions, then store them in an airtight container in the fridge for up to 4 days. Reheat gently in the oven or in a frying pan until warmed through.

Frequently asked questions