Caramelized Onion and Baby Spinach Stuffed Pasta Shells

Caramelized onions and gooey cheese are awesome together any way you look at it, and when stuffed inside pasta shells? They taste positively outstanding 😋👌! 


About the recipe

I’ve made stuffed pasta shells before with spinach and onions,  but this time I caramelized the onions with a little garlic giving the dish a lovely sweet oniony flavor that tastes wonderful along with spinach and ricotta cheese.


More onions mean more flavor

I used lots of onions to really amp up the caramelized onion flavor because no matter how much onion you use it always condenses down to very little.


And by the time the caramelized onions are mixed in with the ricotta, mozzarella cheese and spinach, the onion flavor becomes even more subdued. So go ahead and use as much onions as you want, because more onions means more flavor.

A great make ahead recipe

This is a great recipe to make ahead and leave in the refrigerator until you are ready to bake. Or bake and keep in the refrigerator until ready to serve.


The recipe makes a large quantity for a party or for two dinners – one for tonight and one for later. Cheesy, with lots of good for you spinach and sweet oniony flavor, this pasta is deliciously good!


Caramelized Onions and Baby Spinach Stuffed Pasta Shells
makes 30 stuffed shells


  • 1 lb baby spinach finely cut
  • 3 large onions or 4 medium onions finely cut
  • 6 garlic cloves minced
  • 30 oz ricotta cheese
  • 2 cups shredded mozzarella cheese
  • 2 cups Gruyere cheese shredded
  • 1 cup white cheddar cheese shredded
  • 1 cup shredded Parmesan cheese (for topping)
  • 4 eggs
  • Salt and pepper
  • 2 jars of store-bought marinara sauce
  • 2 tbsp Olive oil
  • 2 tbsp butter
  • Jumbo pasta shells – 30 count
  • Fresh basil for garnish
  • 2 large baking pans
  • 2 tsp Paprika


  • Warm 2 tbsp butter and 2 tbsp olive oil in a pan and cook onions and garlic until caramelized – about 5-7 minutes.  Let cool and set aside.
  • In the meantime cook pasta shells until cooked al dente. Drain and set aside.
  • In a large bowl mix ricotta cheese with eggs, spinach, caramelized onions, all the cheeses except Parmesan cheese (save this for the topping), add salt and pepper. Mix until well incorporated.
  • Stuff pasta shells with the ricotta spinach mix.
  • In two large baking dishes drizzle some olive oil and spread some pasta sauce on the bottom to coat the dish. Now place the stuffed pasta shells. Top the shells with more pasta sauce. Sprinkle Parmesan cheese on top of the shells and a light dusting of paprika.
  • Cover with aluminium foil and bake for 45min – 1 hour until the stuffing is cooked through.  Remove the foil and broil for 2-3 minutes to make the cheese topping  bubbly and brown.  Take the pasta shells out of the oven and let it sit for 30 minutes to allow the stuffing to settle and bind together before serving.
  • Serve pasta shells with a side salad and garlic bread for a delicious gourmet style stay-at-home dinner.

10 thoughts on “Caramelized Onion and Baby Spinach Stuffed Pasta Shells”

  1. This sounds absolutely lovely, Kalpana!! I recently have really grown to love caramelized onions- they add such pizzaz to a dish! Thank you for sharing this awesome recipe 🙂

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