How to roast onions to bring out their sweetness?

Question

Get the method to turn onions deeply golden, soft, and sweet.

Answer 1

To roast onions to bring out their sweetness, peel and cut them into thick wedges or slices, toss lightly with oil, salt, and pepper, and roast at a moderate to high temperature (190-220°C / 375-425°F) until deeply caramelized and tender.

Detailed Explanation:

Roasting transforms the sharp pungency of raw onions into a wonderfully sweet, mellow, and savory delight. The natural sugars caramelize, creating a rich flavor.

1. Preparation:
   • Choose Onions: Yellow, red, or even sweet Vidalia onions work well. Shallots are also excellent roasted.
   • Peel and Cut: Peel the onions. For most roasting, cut them into thick wedges (e.g., quartered, then halved again) or thick slices (at least 1/2-inch thick). Keep the root end intact for wedges if possible, as it helps hold the layers together.
   • Dry: Ensure the pieces are relatively dry before oiling.
2. Seasoning:
   • Oil: In a large bowl, toss the onion pieces with a generous drizzle of high-smoke-point oil (like olive, canola, or grapeseed). Ensure all surfaces are lightly coated.
   • Salt & Pepper: Season generously with salt and freshly ground black pepper.
   • Optional: A touch of balsamic vinegar or a tiny drizzle of maple syrup/honey in the last 15 minutes can enhance caramelization. Herbs like thyme or rosemary also pair well.
3. Roasting:
   • Hot Pan & Temperature: Place your empty baking sheet in the oven while it preheats to 190-220°C (375-425°F). Spread the onions in a single layer on the hot pan.
   • No Overcrowding: Give them space to roast, not steam. Use two pans if necessary.
   • Bake Time: Roast for 25-40 minutes, depending on the size of the cuts and desired level of caramelization.
   • Flip/Stir: Flip or stir the onions once or twice during roasting to ensure even browning.
   • Doneness: Onions are done when they are deeply caramelized, soft, and sweet. Don't be afraid of dark brown edges, as that's where a lot of the flavor is!

Pro Tip:

For an even deeper sweetness, you can roast whole, unpeeled onions (after trimming ends) for an hour or more, then peel and mash the softened, caramelized insides.