What kind of onion is best for roasting?

Yellow onions and red onions are best for roasting, as their naturally sweet flavor deepens as they cook. Plus, they hold up well to high heat and maintain their vibrant hue.

How long do roasted onions last?

Roasted onions typically last for three to four days when stored properly in an airtight container.

French Onion–Stuffed Onions

Active Time:

30 mins

Total Time:

1 hr 15 mins

Servings:

Stuffing an onion with more onion may seem like overkill — that is, until you bite into this rich and savory dish by F&W food editor Paige Grandjean. The onions hold their shape during baking, while the juices from the vegetable and the caramelized onions that are packed into the slightly hollowed center are soaked up into a slice of sourdough bread. Topped with Gruyère that melts over the roasted onion, the whole dish becomes a fork-and-steak-knife version of French onion soup gratinée. Try this recipe with a yellow onion or red onion — either will work with wonderful results. Overall, it’s an inviting dish that will turn heads at the table. Serve it as a vegetarian main course or as a side dish.

Frequently Asked Questions

What kind of onion is best for roasting?

Yellow onions and red onions are best for roasting, as their naturally sweet flavor deepens as they cook. Plus, they hold up well to high heat and maintain their vibrant hue.
How long do roasted onions last?

Roasted onions typically last for three to four days when stored properly in an airtight container.

Notes from the Food & Wine Test Kitchen

Choose nicely uniform onions for even cooking. Onions that are more squat in shape (instead of long) are good, as they will have a wider opening for easier stuffing.

Don’t be afraid to really pile it up when assembling the onions (even if it looks a bit precarious). It may look like a lot, but the cheese melts down, and it’s nice to be able to see bits of the onion filling and the cheese spilling out and down the sides.

Make ahead

Onions can be prepared through step 1 and stored in an airtight container in the refrigerator for up to one day. Proceed with the recipe as directed.

You can hollow out the onions up to one day in advance. Store them airtight in the fridge (and don’t forget to save the chopped-up insides).

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Ingredients

4 (about 12-ounce) white onions
1 cup beef stock
2 tablespoons olive oil, divided
1/4 teaspoon kosher salt, plus more to taste
1/4 teaspoon black pepper, plus more for garnish
1 cup Frenched Onions, warmed
3/4 teaspoon chopped fresh thyme, plus additional leaves for garnish
1 1/4 cups Gruyère cheese, shredded (about 5 ounces), divided
4 (3/4-inch-thick) slices rustic sourdough bread

Directions

Preheat oven to 450°F. Trim about 1/4 inch from the root end and about 1 inch from the stem end of each onion. Peel onions, and remove outermost onion layer. Scoop out flesh from center of each onion using a small spoon to create a cavity about 1 inch deep, leaving about 2 onion layers intact around the sides. The base should be slightly thicker. Reserve onion flesh. Discard peels, trimmings, and the outer onion layer.
Finely chop onion flesh. Spread 1 1/2 cups chopped onion in a 9-inch square baking pan, and pour in beef stock. (Discard any remaining flesh, or reserve for another use.) Nestle hollowed onions, open end up, in pan; drizzle with 1 tablespoon oil, and sprinkle evenly with salt and pepper.
Cover pan tightly with aluminum foil. Bake in preheated oven until hollowed onions are softened, about 20 minutes. Uncover, and continue baking until liquid in pan has almost completely evaporated and hollowed onions are tender, 20 to 25 minutes. Remove pan from oven. (Do not turn oven off.)
Transfer hollowed onions to a paper towel–lined plate. Stir Frenched onions and thyme into onion mixture in pan. Season to taste with additional salt. Stuff each hollowed onion with 1 tablespoon Gruyère and about 1/3 cup Frenched onion mixture.
Place bread slices on a rimmed baking sheet; drizzle evenly with remaining 1 tablespoon oil. Top each slice with 1 stuffed onion. Sprinkle onions evenly with remaining 1 cup Gruyère, letting some spill onto bread. Bake at 450°F until Gruyère is melted and beginning to brown, 5 to 8 minutes. Garnish with thyme leaves and additional black pepper. Serve hot.