When you need a cozy dinner that feels a little special without asking for a long ingredient list, these oven baked 4-ingredients creamy caramelized onion shells are such a good one to keep in your back pocket. The sweetness of caramelized onions melts right into a creamy sauce, and the baked cheese on top gives the whole dish that golden, bubbly finish everybody reaches for first. It has that comforting, casserole-style feel that works just as well for a weeknight family supper as it does for taking over to someone you love.
This pasta is rich and satisfying on its own, so I like to serve it with simple sides that balance it out, like a crisp green salad, steamed broccoli, or roasted green beans. A basket of warm garlic bread is always welcome if you want to stretch the meal for bigger appetites, and for a more complete dinner, a little rotisserie chicken or sliced sausage on the side pairs nicely with the sweet onions and creamy shells.
Oven Baked 4-Ingredients Creamy Caramelized Onion Shells
Servings: 6
Ingredients
12 ounces medium pasta shells
2 cups caramelized onions
1 1/2 cups Alfredo sauce
2 cups shredded mozzarella cheese
Directions
1. Preheat your oven to 375°F and lightly grease a rectangular glass baking dish.
2. Cook the pasta shells in salted water until just al dente, then drain well.
3. In a large mixing bowl, stir together the cooked shells, caramelized onions, Alfredo sauce, and 1 1/2 cups of the mozzarella until everything is evenly coated.
4. Spoon the mixture into the prepared baking dish and spread it into an even layer. Sprinkle the remaining 1/2 cup mozzarella over the top.
5. Bake uncovered for 20 to 25 minutes, until hot and bubbly and the cheese on top is fully melted with lightly golden spots.
6. Let it rest for 5 minutes before serving so the sauce settles a bit and the shells hold together nicely on the plate.
Variations & Tips
Add a protein: If you want to make this heartier, stir in cooked shredded chicken, browned Italian sausage, or diced ham before baking. It is a great way to turn this side-style pasta into a full one-pan dinner.
For picky eaters: If someone in your house is unsure about onions, chop the caramelized onions even smaller before mixing them in. That way you keep all that sweet flavor, but the texture blends right into the creamy shells.
Change the cheese: Mozzarella gives you that gooey, melty top, but provolone, Monterey Jack, or an Italian blend also work well. A little Parmesan on top can add a nice savory finish too.
Make-ahead tip: You can assemble the dish a day in advance, cover it, and refrigerate until you are ready to bake. If it is going into the oven cold, just add a few extra minutes to the baking time.
Keep it creamy: Be careful not to overcook the pasta before baking, since it will continue to soften in the oven. Pulling the shells at al dente helps the finished dish stay creamy instead of mushy.