This is a dependable, weeknight-friendly casserole that feeds a crowd without drama. Big pasta shells cradle a creamy ricotta and spinach filling, a blanket of marinara on the bottom, and a melted mozzarella lid. It’s straightforward to pull together and forgiving if you follow a few simple rules.
You can make this for a family dinner or a potluck and expect leftovers that reheat well. The method focuses on texture: shells cooked just shy of tender, spinach squeezed dry, and a final broil for color. I’ll walk you through the exact steps, common swaps, and what to watch for so the results are consistently good.
Below you’ll find the ingredient list, the exact stepwise directions, and practical notes from testing. Read the recipe once, then cook with confidence.
Gather These Ingredients
Ingredients
- 24 uncooked jumbo shells — the pasta you’ll fill; cook nearly to al dente so they hold their shape.
- 1 (24 ounce) jar marinara sauce — the base layer to keep shells moist and add flavor.
- 16 ounces frozen spinach, thawed — squeeze out as much water as possible so the filling isn’t runny.
- 15 ounces ricotta cheese — the creamy center; use whole-milk ricotta when possible for richness.
- 1 cup freshly grated Parmesan cheese — adds salty, nutty depth to the filling.
- 1 egg — binds the filling so it holds together after baking.
- 1/2 teaspoon salt — seasons the filling; adjust if your cheeses are very salty.
- Pepper to taste — fresh black pepper wakes the filling up.
- 1/2 teaspoon Italian seasoning — a quick herb boost; oregano, basil, and thyme blend works well.
- 1/2 teaspoon garlic powder — gives gentle garlic flavor without chopping fresh cloves.
- 2 cups shredded mozzarella cheese — the melty topping that browns under the broiler.
- For serving: fresh basil and/or chopped parsley — optional, to taste; bright herbs finish the dish.
Spinach and Ricotta Stuffed Shells Made Stepwise
- Position an oven rack in the top third of the oven and preheat the oven to 375°F (190°C).
- Pour the jar of marinara sauce (24 ounces) into the bottom of a 9×13-inch casserole dish and spread it evenly.
- Bring a large pot of water to a rolling boil. Add the 24 uncooked jumbo shells and cook them for 1 minute less than the time indicated on the package. Drain the shells in a colander and let them sit until they are cool enough to handle.
- While the shells cook (or while they are cooling), make the filling: if the 16 ounces of frozen spinach is not yet thawed, thaw it completely. Squeeze or press the thawed spinach to remove as much liquid as possible.
- Transfer the drained spinach to a mixing bowl. Add the 15 ounces ricotta cheese, 1 cup freshly grated Parmesan cheese, 1 egg, 1/2 teaspoon salt, pepper to taste, 1/2 teaspoon Italian seasoning, and 1/2 teaspoon garlic powder.
- Stir the filling ingredients until they are well combined and evenly mixed.
- Using a small spoon, fill each cooked jumbo shell with the spinach–ricotta mixture. Place each filled shell into the marinara in the casserole dish, arranging them in a single layer (seam-side up if possible).
- Once all shells are in the dish, sprinkle 2 cups shredded mozzarella cheese evenly over the top of the shells.
- Cover the casserole dish tightly with foil and bake in the preheated oven for 30 minutes.
- Remove the foil and switch the oven to broil. Broil the casserole for a few minutes, watching carefully, until the cheese is browned to your liking.
- Remove from the oven and serve immediately. Garnish with fresh basil and/or chopped parsley if using, and season with extra salt and pepper to taste.
What You’ll Love About This Recipe
The texture contrast is the first thing: tender pasta, creamy filling, and bubbly browned cheese. It’s hearty without being heavy, and the spinach adds color and a vegetable component that kids often overlook in favor of the cheese.
It’s also highly scalable. The ingredients are straightforward and available year-round. Prep time is mostly hands-off: boiling shells, squeezing spinach, and mixing. Once assembled, the oven does the rest. That makes this an ideal dish for a relaxed weekend or a no-fuss weeknight.
Ingredient Swaps & Substitutions
If you need to adapt what’s in your kitchen, here are safe swaps that keep the spirit of the dish:
- Ricotta: You can mix part cottage cheese (drained) with ricotta to stretch the filling, but texture will change.
- Frozen spinach: Substitute with roughly 6–8 cups fresh spinach sautéed until wilted and well-drained if you prefer fresh. Make sure it’s squeezed dry.
- Mozzarella: A blend of provolone or fontina with mozzarella gives a slightly more complex top layer.
- Marinara jar: Use homemade or a good-quality canned tomato sauce; if it’s thin, simmer to reduce and concentrate flavor before using.
Setup & Equipment
Minimal equipment makes this approachable. Line up the right pieces before you start for a smooth workflow.
- Large pot — for boiling the shells.
- Colander — to drain pasta efficiently.
- Mixing bowl — to combine the filling.
- 9×13-inch casserole dish — the specified size ensures even baking and that the sauce-to-shell ratio works.
- Small spoon or piping bag — for filling shells; a small spoon works fine, but a piping bag speeds things up.
- Aluminum foil — to cover during baking so the filling steams and melts without drying.
- Oven with broil function — to brown the cheese at the end.
Easy-to-Miss Gotchas
Soggy filling. If you don’t remove enough liquid from thawed spinach the filling can be watery and won’t set. Press it between paper towels or a clean kitchen towel until fairly dry.
Overcooked shells. They’ll fall apart while you fill them. Cook the shells for exactly one minute less than package time as the recipe instructs, then shock in cold water only if you need to stop cooking immediately. Let them cool enough to handle before filling.
Uneven baking. Use the top third rack for an even broil and good cheese browning. If the cheese is browning too fast, move the dish down a rack for the remainder of the broil or reduce the broil time.
Smart Substitutions
Want to lighten the dish or change the flavor profile? Try these smart swaps that don’t break the recipe’s structure.
- Lower-fat ricotta — swap in part-skim ricotta to reduce calories, but expect a slightly less creamy mouthfeel.
- Spice boost — add a pinch of red pepper flakes to the filling or a swirl of spicy arrabbiata sauce for heat.
- Herb swap — swap Italian seasoning for a tablespoon of chopped fresh basil and oregano for a brighter, fresher note.
- Vegan option — use a firm tofu blended with nutritional yeast and lemon in place of ricotta, and a dairy-free mozzarella substitute; results will differ in texture.
What I Learned Testing
The recipe is forgiving, but a few small decisions make the biggest difference. First, thoroughly draining the spinach is non-negotiable. Even a little excess water dilutes the filling and creates a soggy bake. I squeezed in batches with a towel and saw a marked improvement.
Second, filling technique matters. Use a small spoon or a zip-top bag with a corner snipped for speed and cleaner-looking shells. Piping yields uniform portions; spooning is fine for a homier look.
Finally, don’t skip the broil. The casserole will be fully cooked after the covered bake, but that final blast gives the cheese the appetizing brown and textural lift that makes people reach for seconds.
Cooling, Storing & Rewarming
Cool the casserole for about 20–30 minutes at room temperature before storing. This helps the filling set and makes reheating cleaner.
To store: cover tightly and refrigerate for up to 3–4 days. For longer storage, freeze assembled (before baking) for up to 2 months. If baking from frozen, add about 20–30 minutes to the covered baking time and keep an eye on the broil step so the top doesn’t burn.
To reheat: in the oven, cover and warm at 350°F (175°C) for 15–20 minutes or until heated through, then uncover and broil briefly to refresh the top. In the microwave, reheat individual portions in short intervals, stirring or flipping once to ensure even heating.
Reader Questions
Q: Can I make this ahead? A: Yes. Assemble, cover tightly, and refrigerate for up to 24 hours before baking. Bake covered for the same time; add a few extra minutes if the dish is chilled all the way through.
Q: My shells fell apart while filling. What happened? A: They were likely overcooked. Next time reduce the boiling time by another minute and handle gently. Cool them enough to pick up without tearing.
Q: Do I have to use a 9×13-inch dish? A: That size matches sauce and shell quantities for even baking. You can use a similar-volume dish, but baking times may vary slightly.
Hungry for More?
If you like this, try swapping the filling for a meat-based ragu or roasted vegetables for a change of pace. Other baked pasta dishes like lasagna or manicotti follow similar assembly logic and are great next steps.
Come back and tell me how yours turned out—what you swapped, what you loved, and any tips you picked up. Cooking is better when we learn from each other.
Spinach and Ricotta Stuffed Shells
Ingredients
Ingredients
- 24 uncooked jumbo shellssee note
- 1 24 ounce jarmarinara sauce
- 16 ouncesfrozen spinachthawed
- 15 ouncesricotta cheese
- 1 cupfreshly grated parmesan cheese
- 1 egg
- 1/2 teaspoonsalt
- Pepperto taste
- 1/2 teaspoonItalian seasoning
- 1/2 teaspoongarlic powder
- 2 cupsshredded mozzarella cheese
- For serving: fresh basil and/or chopped parsleyoptional to taste
Instructions
Instructions
- Position an oven rack in the top third of the oven and preheat the oven to 375°F (190°C).
- Pour the jar of marinara sauce (24 ounces) into the bottom of a 9×13-inch casserole dish and spread it evenly.
- Bring a large pot of water to a rolling boil. Add the 24 uncooked jumbo shells and cook them for 1 minute less than the time indicated on the package. Drain the shells in a colander and let them sit until they are cool enough to handle.
- While the shells cook (or while they are cooling), make the filling: if the 16 ounces of frozen spinach is not yet thawed, thaw it completely. Squeeze or press the thawed spinach to remove as much liquid as possible.
- Transfer the drained spinach to a mixing bowl. Add the 15 ounces ricotta cheese, 1 cup freshly grated Parmesan cheese, 1 egg, 1/2 teaspoon salt, pepper to taste, 1/2 teaspoon Italian seasoning, and 1/2 teaspoon garlic powder.
- Stir the filling ingredients until they are well combined and evenly mixed.
- Using a small spoon, fill each cooked jumbo shell with the spinach–ricotta mixture. Place each filled shell into the marinara in the casserole dish, arranging them in a single layer (seam-side up if possible).
- Once all shells are in the dish, sprinkle 2 cups shredded mozzarella cheese evenly over the top of the shells.
- Cover the casserole dish tightly with foil and bake in the preheated oven for 30 minutes.
- Remove the foil and switch the oven to broil. Broil the casserole for a few minutes, watching carefully, until the cheese is browned to your liking.
- Remove from the oven and serve immediately. Garnish with fresh basil and/or chopped parsley if using, and season with extra salt and pepper to taste.
Equipment
- Oven
- 9×13-inch Casserole Dish
- Large Pot
- Colander
- Mixing Bowl
- small spoon
- Aluminum Foil
Notes
Generally, jumbo shells come in 12 ounce packages. It’s a good idea to boil the whole pack (or a few more than the 24 shells the recipe calls for) since some of the shells will break. Also, the actual number of shells you will use depends on how full you stuff them and how many shells you can fit in your baking dish. The size of “jumbo” shells can vary from brand to brand.
You can use fresh spinach if you prefer. Simply sauté 16 oz. of fresh baby spinach in a skillet until wilted, let it cool, and then chop it.
See blog post for make ahead and freezing tips.
This recipe can also be found on page 61 of theSalt & Lavender: Everyday Essentialscookbook.
