5-Ingredient Sausage-Stuffed Onions

updated Mar 16, 2020
5-Ingredient Sausage Stuffed Onions

With a triple layer shell, the onions are sturdy, yet melt in your mouth tender and filled with a savory sausage, mushroom, and spinach stuffing.


Prep20 minutes to 25 minutes

Cook1 hour

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9x13 pan filled with sausage stuffed onions
Credit: Photo: Joe Lingeman; Food Styling: Jesse Szewczyk

Stuffed onions — yes, onions! — are the best thing you’re probably not making. The bite of these alliums is sharp when raw, but a double bake seriously mellows their flavor, giving them a mild, gentle sweetness that’s the perfect vessel for savory stuffings. With a triple-layer shell, the onions are sturdy enough to hold the sausage, mushroom, and spinach filling, while still being melt-in-your-mouth tender. It’s a humble meal made of mostly pantry and freezer staples (and as long as you remember to use no-sugar sausage, it’s also Whole30-friendly).

Credit: Photo: Joe Lingeman; Food Styling: Jesse Szewczyk

How to Prep Onions for Stuffing

I recommend sticking with basic white onions, which are large and often uniform in size, with tender, mild flesh. The easiest and fastest way to make stuffed onions is by cutting the onions in half. Trim one-half inch from the top of the onion, then cut the onions in half from pole to pole and remove the outer papery layers. Next, it’s time to remove the inner onion layers, leaving three outer layers of the onions intact, which is just enough for a shell that’s sturdy, but tender.

The Best Way to Use Up Leftover Onion Layers

Don’t toss those inner layers! You can, of course, reserve them for any recipe that calls for chopped or sliced onion, but our favorite way to use them is for caramelized onions. Whether you cook them slowly on the stovetop or opt for a more hands-off method in your slow cooker, your kitchen will be perfumed with the sweet scent of onions. Keep some in the fridge to use right away, then stash the remainder in the freezer (because yes, you can freeze caramelized onions), and use them for future pizzas, pastas, frittatas, and more!

5-Ingredient Sausage Stuffed Onions

With a triple layer shell, the onions are sturdy, yet melt in your mouth tender and filled with a savory sausage, mushroom, and spinach stuffing.

Prep time 20 minutes to 25 minutes

Cook time 1 hour

Serves 6

Nutritional Info


  • 6

    large white onions (12 to 14 ounces each)

  • 2 tablespoons

    plus 1 teaspoon olive oil, divided

  • 8 ounces

    cremini mushrooms

  • 2 cloves


  • 1 (10-ounce) package

    frozen chopped spinach, thawed in the refrigerator overnight or in the microwave

  • 1 pound

    uncooked Italian pork sausage

  • 1/2 teaspoon

    kosher salt

  • 1/4 teaspoon

    freshly ground black pepper


  1. Arrange a rack in the middle of the oven and heat the oven to 400°F. Coat a 9x13-inch baking dish with 1 teaspoon of the olive oil.

  2. Trim the top 1/2-inch from 6 large white onions. Cut the onions in half from pole to pole. Peel and discard the outer papery layers from each half. Carefully remove the inner layers of each onion half, leaving three outer layers in place for the shell. Reserve the inner layers. Place the scooped-out onions in the baking dish flat side up and cover tightly with aluminum foil.

  3. Roast the onion shells until slightly softened, 30 to 40 minutes. Meanwhile, prepare the filling.

  4. Coarsely chop 2 of the inner onion layers (about 1 cup total) and save the remaining onions for another use. Place the chopped onion, 8 ounces cremini mushrooms, and 2 garlic cloves in a food processor fitted with the blade attachment. Pulse in 2-second bursts until finely chopped, about 20 pulses.

  5. Thaw 1 package chopped spinach according to package directions if needed. Squeeze all the excess moisture from the spinach with your hands. Remove the casings from 1 pound Italian sausage if needed.

  6. Heat 1 tablespoon of the olive oil in a large skillet over medium-high heat until shimmering. Add the sausage and cook, breaking it up with a wooden spoon, until browned and cooked through, about 8 minutes.

  7. Reduce the heat to medium and add the remaining 1 tablespoon olive oil, chopped vegetables, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper. Cook, stirring occasionally until softened and the mushrooms release their juices, about 8 minutes. Add the spinach, stir to combine, and cook 2 minutes more.

  8. When the onion shells are ready, evenly divide the sausage mixture among the onions. Bake uncovered until the tops are golden-brown, about 20 minutes.