Equipment
* optional
Ingredients
Vegetables
- 4 yellow or sweet onions, whole
Seasoning
- 60 g unsalted butter, room temperature
- 5 g salt
- 1 g black pepper, freshly ground
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 208 kcal
- Protein
- 3 g
- Carbohydrates
- 24 g
- Fat
- 12 g
- Fiber
- 4 g
- Sugar
- 11 g
- Sodium
- 497 mg
- Saturated Fat
- 8 g
- Monounsaturated Fat
- 4 g
- Polyunsaturated Fat
- 1 g
- Cholesterol
- 32 mg
- Potassium
- 372 mg
- Calcium
- 63 mg
- Iron
- 0.6 mg
- Magnesium
- 26 mg
- Phosphorus
- 77 mg
- Zinc
- 0.4 mg
- Vitamin A
- 103 mcg
- Vitamin C
- 19 mg
- Vitamin E
- 0.4 mg
- Vitamin K
- 2 mcg
- Vitamin B6
- 0.3 mg
- Vitamin B12
- 0.0 mcg
- Thiamin
- 0.13 mg
- Riboflavin
- 0.08 mg
- Niacin
- 0.3 mg
- Folate
- 48 mcg
- Water
- 225 g
Sources: USDA FoodData Central
Method
Preheat your oven to 200°C (400°F). Ensure the oven rack is in the center position.
Peel the onions carefully, removing the papery outer layers but keeping the root end intact to hold the onion together. Slice about 1 cm off the top stem end to create a flat surface.
Using a paring knife or small spoon, carve a small cone-shaped divot (about 2-3 cm deep) into the cut top of each onion to hold the butter.
Place the onions in the baking dish. Press a pat of butter (15g) into the hollow of each onion. Generously season the tops with salt and freshly ground black pepper.
Bake in the preheated oven for 60 minutes. The onions are done when the outer layers are golden brown and a knife slides easily into the center with no resistance.
Remove from the oven and spoon any pan juices over the onions before serving.
Chef's Notes
- Sweet onion varieties like Vidalia or Walla Walla work best for this recipe as they have a higher sugar content that caramelizes beautifully.
- For a deeper flavor profile, add a splash of balsamic vinegar or beef stock to the bottom of the baking dish before cooking.
- Leftover baked onions can be chopped and added to mashed potatoes, soups, or omelets for instant flavor depth.
- If you want to ensure the butter penetrates deeply, you can cut a deep 'X' into the top of the onion instead of scooping out a divot.
Storage
Refrigerator: 3 days — Store in an airtight container. The butter will solidify but melt again upon reheating.
Freezer: 2 months — Texture may become slightly softer upon thawing.
Reheating: Reheat in a 175°C (350°F) oven for 15 minutes or microwave until warm.
Troubleshooting
Onion center is still crunchy
Cause: The onion was too large or the oven temperature fluctuated
Fix: Cover with foil to trap steam and bake for an additional 15-20 minutes
Prevention: Select medium-sized onions or extend cooking time for large ones
Cultural Context
Baked onions are a rustic classic in English and American farmhouse cooking, often served alongside roast meats. While historically associated with peasant food due to the affordability of onions, the slow-roasting method elevates the humble bulb into a dish of surprising elegance and sweetness.
