Baked Onion in Foil Recipe
Baked Onion in Foil is a simple, flavorful side dish that transforms humble onions into sweet, caramelized perfection. Wrapped in foil and slowly baked or grilled, these onions soften beautifully while absorbing herbs and butter. They’re perfect alongside grilled meats, tucked into burgers, or served solo as a low-carb, gluten-free comfort food.
- 2 medium yellow onions
- 2 tablespoons unsalted butter (or olive oil for vegan)
- ½ teaspoon salt
- ¼ teaspoon ground black pepper
- ½ teaspoon dried thyme or rosemary
- Foil for wrapping
Instructions
- Step 1: Preheat your oven to 400°F (200°C) or heat your grill to medium-high.
- Step 2: Peel the onions, then slice a shallow "X" on the top of each to help the butter penetrate while cooking.
- Step 3: Place each onion on a sheet of foil. Top with 1 tablespoon butter, a pinch of salt, pepper, and a sprinkle of herbs.
- Step 4: Wrap the foil tightly around each onion to form a sealed packet. Make sure no steam escapes during cooking.
- Step 5: Place the foil-wrapped onions directly on a baking sheet or grill grate.
- Step 6: Bake or grill for 45-50 minutes until the onions are tender, golden, and caramelized inside.
- Step 7: Let them rest for a few minutes, then carefully open the foil to avoid steam. Serve warm as a side or topping.
Notes
- These onions are excellent for burgers, steak, or mashed potato toppers.
- Use olive oil and skip butter for a vegan version.
- Add a splash of balsamic vinegar for a tangy finish.
- Store leftovers in the fridge for up to 3 days—great reheated or chopped into salads.
- Try red or sweet onions for variation in flavor.
Frequently Asked Questions
Can I make these ahead of time?
Yes. Cook, cool, and reheat in the foil at 350°F for 10 minutes.
Can I add other vegetables?
Absolutely. Carrots, bell peppers, or garlic cloves roast well with the onions.
Can I use red onions instead?
Yes. Red onions give a sweeter, richer flavor when roasted.
Are these suitable for a vegan diet?
Yes, just replace the butter with olive oil or vegan butter.
Do I need to flip the foil packet during grilling?
No, the foil traps enough heat to cook them evenly without flipping.