Name: Spinach Ricotta Stuffed Shells
Prep time: 35 min
Cook time: 35 min
Total time: 80 min
Ingredients: 250 g (9 oz) jumbo pasta shells (about 28); 1 tbsp fine salt, for the pasta water; 1 tbsp (15 ml) olive oil; 1 small onion (about 80 g), finely chopped; 3 garlic cloves, finely chopped; 140 g (5 oz) baby spinach, chopped, or 280 g (10 oz) frozen spinach, thawed and squeezed dry; 450 g (2 cups) whole-milk ricotta, drained if wet; 150 g (1 ½ cups) shredded low-moisture mozzarella; 20 g (¼ cup) finely grated Parmesan; 1 large egg; 1 tsp dried oregano or Italian seasoning; ⅛ tsp freshly grated nutmeg; ¾ tsp fine salt; ¼ tsp black pepper; finely grated zest of ½ lemon (optional); 720 ml (3 cups) marinara sauce; 60 ml (¼ cup) water; 50 g (½ cup) shredded low-moisture mozzarella; 20 g (¼ cup) finely grated Parmesan; fresh basil or parsley, to finish

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Jumbo pasta shells filled with a spinach and ricotta mixture, baked in marinara under mozzarella and Parmesan, are one of the most useful pasta bakes to know. You can put the dish together a day ahead or freeze it unbaked. It feeds a crowd from one 9 × 13-inch dish, and there’s no meat in it.

This version focuses on the things that make the difference between creamy shells and watery ones: well-drained ricotta, spinach squeezed properly dry, shells cooked short of al dente, and enough sauce to keep the pasta tender while it bakes.

Serves 6 (about 24 shells). Prep takes about 35 minutes and the bake about 35 minutes, plus a short rest.

Ingredients

Shells

250 g (9 oz) jumbo pasta shells, about 28 shells (a few extra to allow for tearing)
1 tbsp fine salt, for the pasta water

Spinach and ricotta filling

1 tbsp (15 ml) olive oil
1 small onion (about 80 g), finely chopped
3 garlic cloves, finely chopped
140 g (5 oz) baby spinach, roughly chopped, or 280 g (10 oz) frozen chopped spinach, thawed
450 g (2 cups) whole-milk ricotta
150 g (1 ½ cups) shredded low-moisture mozzarella
20 g (¼ cup) finely grated Parmesan
1 large egg
1 tsp dried oregano or Italian seasoning
⅛ tsp freshly grated nutmeg
¾ tsp fine salt
¼ tsp black pepper
Finely grated zest of ½ lemon (optional)

Sauce and topping

720 ml (3 cups) marinara sauce, jarred or homemade (see below)
60 ml (¼ cup) water
50 g (½ cup) shredded low-moisture mozzarella
20 g (¼ cup) finely grated Parmesan
Fresh basil or parsley, to finish

Notes on the ingredients

Jumbo shells (conchiglioni) vary by brand in size and in how many survive the boil. A 340 g (12 oz) box usually holds around 36 shells, so cooking 250 g gives you spares. Torn shells can be chopped and scattered over the top of the dish.

Ricotta should be whole-milk for a creamy filling. If yours looks wet, or has liquid pooling in the tub, spoon it into a sieve lined with a paper towel and leave it to drain in the fridge for 30 minutes, or overnight if you have time. Watery ricotta is the main reason for a runny filling.

Spinach shrinks dramatically. Fresh baby spinach is wilted in the pan with the onion, then cooled. If you use frozen, thaw it, then squeeze it in a clean tea towel until no more liquid comes out. You should end up with about 140 g (⅔ cup) of compact spinach.

Mozzarella here is the low-moisture block kind, grated. Fresh mozzarella releases too much water in a long bake.

Marinara. A good jar is fine. For homemade, warm 3 tbsp (45 ml) olive oil with 3 sliced garlic cloves over low heat until fragrant, add an 800 g (28 oz) can of crushed tomatoes, 1 tsp salt and a few basil leaves, and simmer for 20–25 minutes until slightly thickened. That makes about 750 ml (3 cups).

Method

Heat the oven to 190°C (375°F), or 170°C (340°F) fan. Lightly oil a 23 × 33 cm (9 × 13-inch) baking dish.
Boil the shells. Bring a large pot of water to the boil with the salt. Cook the shells for 2 minutes less than the packet says. They should still be firm, as they finish cooking in the oven. Stir gently once or twice early on so they don’t stick together.
Cool the shells. Drain carefully, rinse briefly under cool water to stop the cooking, and spread them out, open side down, on an oiled tray so they don’t stick.
Cook the spinach. Meanwhile, warm the olive oil in a frying pan over medium heat. Cook the onion for 4–5 minutes, until soft and translucent. Add the garlic for 30 seconds, then the spinach a handful at a time, and cook for 2–3 minutes until wilted and the pan is nearly dry. Tip onto a plate and let it cool for 10 minutes. If there’s liquid, press it out with the back of a spoon.
Make the filling. In a large bowl, mix the ricotta, mozzarella, Parmesan, oregano, nutmeg, salt, pepper and lemon zest, if using. Fold in the cooled spinach, then taste and adjust the salt; the filling should be well seasoned. Beat in the egg last.
Sauce the dish. Stir the water into the marinara. Spread about half of it over the base of the dish.
Fill the shells. Spoon about 2 tablespoons of filling into each shell, or pipe it from a freezer bag with a corner snipped off. Set the shells open side up in the dish in snug rows.
Top. Spoon the rest of the sauce over and between the shells, leaving some of the filling visible. Scatter over the mozzarella and Parmesan.
Bake. Cover tightly with foil and bake for 20 minutes, until the sauce bubbles at the edges. Uncover and bake for another 12–15 minutes, until the cheese has melted and is spotted golden. The centre of a shell in the middle of the dish should be piping hot, 74°C (165°F) if you check.
Rest for 10 minutes so the filling sets a little, then scatter over basil or parsley and serve.

Filling the shells without tearing them

Undercooking is the main trick: shells boiled to fully soft are floppy and split when you open them. Cook a couple of extras, and handle each shell by its back. Hold it in one hand, cupping it slightly open, and spoon or pipe in the filling with the other. A piping bag is faster and neater for a full dish. Don’t overfill. A shell that is slightly domed is right; anything spilling over will run into the sauce.

Common mistakes

Watery filling. Drain the ricotta and dry the spinach well. Excess water seeps out in the oven and thins the sauce.
Too little sauce. Any pasta left uncovered and exposed in the oven turns leathery. Make sure most of each shell sits in or under sauce.
Skipping the foil. The covered first half steams the shells tender. Without it, the edges dry out before the middle is hot.
Bland filling. Ricotta needs salt. Season the filling until it tastes good on its own.
Cutting straight away. Straight from the oven, the filling runs out of the shells. Ten minutes makes it much easier to serve.

Substitutions and variations

Cheese: drained small-curd cottage cheese can replace up to half the ricotta. Blend it briefly for a smoother texture. Pecorino Romano can stand in for Parmesan, but it’s saltier, so reduce the salt slightly.
Vegetables: replace some of the spinach with finely chopped sautéed mushrooms, roasted courgette or chopped artichoke hearts, all cooked until dry.
Meat: brown 300 g (10 oz) Italian sausage, removed from its casings, and stir it into the marinara.
Gluten-free: gluten-free jumbo shells exist but are fragile. Cook them very firm and handle them gently.
Egg-free: leave out the egg. The filling will be slightly softer but still holds.
Rosé sauce: stir 120 ml (½ cup) double cream into the marinara for a richer, pink sauce.

Make ahead, freezing and reheating

Make ahead: assemble the dish completely, cover and refrigerate for up to 24 hours. Take it out of the fridge while the oven heats and add 10 minutes to the covered baking time.
Freeze unbaked: assemble in a freezer-safe and oven-safe dish, wrap well in cling film and foil, and freeze for up to 2 months. Bake from frozen, covered, at 190°C (375°F) for 50–60 minutes, then uncover for 15 minutes, until the centre is piping hot.
Leftovers: cool and refrigerate within 2 hours, and eat within 3 days. Reheat individual portions in the microwave, covered, or the dish in a 180°C (350°F) oven under foil for 20–25 minutes, with a spoonful of water or extra sauce to stop it drying out.

What to serve with stuffed shells

A sharp green salad with a lemony dressing balances the richness. Garlic bread or simple crusty bread helps with the sauce, and roasted broccoli or green beans make it a full meal. If you are planning an Italian evening at home, the same tomato sauce and mozzarella turn up on our homemade Margherita pizza, and our homemade potato gnocchi is good with the same marinara.

A little background

Stuffed pasta shells, conchiglioni ripieni, are cooked in Italy, where they may be filled with ricotta, meat or vegetables and baked in tomato sauce or béchamel. The version most people picture, with jumbo shells baked in marinara under mozzarella, is largely an Italian-American dish, part of the same family as baked ziti, manicotti and lasagne. These are generous, make-ahead dishes that became staples of Sunday dinners, holidays and potlucks. Spinach and ricotta is the classic meat-free filling, the same combination used in ravioli and cannelloni.

For more on cooling, freezing and reheating, see our make-ahead, storage and freezing guide.