I cooked large uncooked pasta shells directly in the slow cooker and filled them with a creamy mixture of frozen spinach and cheeses to make my Spinach Stuffed Shells that come together in the pot.

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I didn’t think cooking raw pasta in a slow cooker could turn out well, but when I first made a batch with uncooked pasta shells and ricotta cheese I was wrong. It felt like breaking kitchen rules, and yet there was something oddly convincing about the finish.

If you like Slow Cooker Pasta Recipes this Spinach Stuffed Shells riff will mess with your expectations in a good way. It’s messy, kind of stubborn, and a little genius, the sort of dinner you’ll tell friends about even though it shouldn’t work.

I still can’t explain all of it, but I can’t stop making it.

Ingredients

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Jumbo shells pack carbs and calories, they’re great for holding filling and soaking sauce
Marinara brings tomato tang, vitamin C, fibre and savory sweetness to quickly balance cheeses
Ricotta is creamy offers protein and calcium makes filling rich but not heavy
Frozen spinach adds iron, fiber, mild earthiness, saves time and blends into filling
Mozzarella melts gooey gives stretchy cheese pull, mostly fat and protein and milky notes
Parmesan lends salty umami, a little goes far for extra savory depth and crisp finish
Garlic and onion boost aroma and flavor they also bring antioxidants and subtle sweetness

Ingredient Quantities

1 12 oz box jumbo uncooked pasta shells (about 24 shells)

24 oz marinara sauce (about 3 cups)

15 oz ricotta cheese container

1 10 oz package frozen chopped spinach

2 cups shredded mozzarella cheese

1/2 cup grated Parmesan cheese

1 large egg

2 garlic cloves

1 small onion

1 teaspoon Italian seasoning

1/2 teaspoon salt

1/4 teaspoon black pepper

2 tablespoons chopped fresh parsley (optional)

1 tablespoon olive oil (optional)

How to Make this

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1. Prep the veg and spinach: finely chop the onion and mince the garlic; thaw the frozen spinach in the microwave or cold water and squeeze it very dry so the filling won’t be watery.

2. Sweat the onion and garlic: heat the olive oil in a small skillet over medium heat, cook the onion until soft and translucent about 4 minutes, add the garlic for 30 seconds just to smell it, then let cool a bit.

3. Make the filling: in a bowl combine the ricotta, drained chopped spinach, the cooked onion and garlic, 1 cup of the shredded mozzarella, the grated Parmesan, the egg, Italian seasoning, salt and pepper, and most of the chopped parsley (save a little for garnish). Mix until evenly combined, taste and adjust salt if needed.

4. Pour a little sauce in the slow cooker: spread about 3/4 cup of the marinara on the bottom of a 6 to 7 quart slow cooker so the shells won’t stick.

5. Stuff the shells: using a teaspoon or small spoon, fill each uncooked jumbo shell with the ricotta-spinach mixture (don’t mound it too high or they won’t sit right), then place them seam side up in a single snug layer in the slow cooker.

6. Add remaining sauce and cheese: spoon the rest of the marinara over the arranged shells ensuring most tops are covered; if your sauce is very thick add up to 1/2 cup water to help the pasta cook. Sprinkle the remaining mozzarella evenly over the top and a little extra Parmesan if you like.

7. Cook: cover and cook on LOW for 2 1/2 to 3 hours or on HIGH for 1 1/2 to 2 hours, until the shells are tender and the filling feels set and the cheese is bubbly. Times vary by slow cooker so check at the lower end of the range.

8. Rest before serving: turn off the slow cooker and let the dish sit covered for 10 to 15 minutes so it firms up and is easier to serve.

9. Serve and finish: garnish with the remaining fresh parsley, scoop out carefully with a spatula and serve with extra Parmesan and a simple salad. If any shells stuck a bit use a thin spatula to loosen them.

Equipment Needed

1. 6 to 7 quart slow cooker — the main cooking vessel
2. Small skillet (8 inch) to sweat the onion and garlic
3. Large mixing bowl for the ricotta and spinach filling
4. Cutting board and a sharp chef’s knife for chopping veg
5. Measuring cups and spoons for sauce, cheese and seasonings
6. Teaspoon or small spoon for stuffing each jumbo shell
7. Fine mesh sieve or a clean kitchen towel to squeeze the thawed spinach dry
8. Rubber spatula plus a thin metal or offset spatula for spreading sauce and serving, and to loosen stuck shells

Note: don’t overfill the shells and have a plate or tray nearby to line up the filled shells before dropping them into the slow cooker.

FAQ

Q: Do I need to thaw and squeeze the frozen spinach? A: Yes, thaw it and squeeze out as much water as you can, or the filling gets watery and the sauce gets diluted. I usually wrap it in a dish towel and really press, works great.

Q: Do the jumbo shells need to be boiled first? A: Not required, the uncooked shells will cook in the slow cooker if theyre covered with sauce and theres enough moisture. If you like firmer pasta you can boil them 4 to 6 minutes, drain and cool before stuffing.

Q: How long and what setting do I cook them on? A: Cook on low for about 3 to 4 hours or on high for 2 to 2.5 hours. Check at the lower end, overcooking can make shells mushy so dont leave it too long.

Q: Can I sauté the onion and garlic first? A: Yes thats a great trick, sautéing in a little olive oil softens and sweetens them and adds big flavor. But you can also add them raw if youre short on time, it still works.

Q: Can I make ahead or freeze these? A: You can assemble ahead and refrigerate overnight, or freeze before cooking up to 2 months. Thaw in fridge before cooking and add 30 to 60 extra minutes. Cooked leftovers freeze well too, about 2 months, thaw overnight and reheat covered.

Q: Any tips to stop the dish from getting dry or watery? A: Use enough sauce and spread some on the bottom so shells sit in moisture, add 1/4 to 1/2 cup water if your sauce is super thick. Don’t overfill the slow cooker, cook covered and check toward the end. Also the ricotta mixture should reach about 165°F for safety.

Slow Cooker Stuffed Shells With Spinach Recipe Substitutions and Variations

Ricotta cheese: swap with blended cottage cheese for the same texture, silken tofu for a vegan option, or mascarpone mixed with a bit of Greek yogurt for extra creaminess. Use the same amount and taste for salt.
Frozen chopped spinach: use fresh baby spinach (about 6 to 8 cups before wilting) sautéed and well squeezed, or frozen chopped kale thawed and drained, or well drained canned spinach. If using fresh, cool it before mixing so your filling isnt watery.
Jumbo uncooked pasta shells: substitute manicotti tubes, use large pre cooked refrigerated shells, or cut lasagna noodles into rectangles and roll the filling inside. Adjust cook time if using pre cooked pasta.
Large egg: make a flax egg (1 tablespoon ground flax mixed with 3 tablespoons water) for a vegan binder, use 1/4 cup plain yogurt, or omit and add an extra 1/4 cup grated Parmesan to help hold things together. Let flax mix sit a minute to thicken before adding.

Pro Tips

1) Squeeze the spinach until it’s almost bone dry — use a clean dish towel or cheesecloth and really twist. If any moisture’s left the filling gets runny and the shells slide around, trust me it makes a huge difference.

2) Chill the filling for 10 to 15 minutes before stuffing, or pop it in the freezer for 5. It firms up so you can spoon it neatly into the shells without it collapsing or oozing everywhere.

3) Use a small cookie scoop or a teaspoon so every shell gets the same amount. Even portions = even cooking and it looks way nicer, plus you won’t overstuff and end up with cracked shells.

4) If you want to make ahead, assemble in the cooker or a baking dish, cover tightly and refrigerate up to 24 hours; for freezing, add a bit more sauce and add extra cook time from frozen. Reheating tip: let it rest after cooking so it sets up, then loosen edges with a thin spatula before serving.

Slow Cooker Stuffed Shells With Spinach Recipe

Recipe by Sarah level

0.0 from 0 votes

I cooked large uncooked pasta shells directly in the slow cooker and filled them with a creamy mixture of frozen spinach and cheeses to make my Spinach Stuffed Shells that come together in the pot.

Servings

servings

Calories

540

kcal

Equipment: 1. 6 to 7 quart slow cooker — the main cooking vessel
2. Small skillet (8 inch) to sweat the onion and garlic
3. Large mixing bowl for the ricotta and spinach filling
4. Cutting board and a sharp chef’s knife for chopping veg
5. Measuring cups and spoons for sauce, cheese and seasonings
6. Teaspoon or small spoon for stuffing each jumbo shell
7. Fine mesh sieve or a clean kitchen towel to squeeze the thawed spinach dry
8. Rubber spatula plus a thin metal or offset spatula for spreading sauce and serving, and to loosen stuck shells

Note: don’t overfill the shells and have a plate or tray nearby to line up the filled shells before dropping them into the slow cooker.

Ingredients

1 12 oz box jumbo uncooked pasta shells (about 24 shells)
24 oz marinara sauce (about 3 cups)
15 oz ricotta cheese container
1 10 oz package frozen chopped spinach
2 cups shredded mozzarella cheese
1/2 cup grated Parmesan cheese
1 large egg
2 garlic cloves
1 small onion
1 teaspoon Italian seasoning
1/2 teaspoon salt
1/4 teaspoon black pepper
2 tablespoons chopped fresh parsley (optional)
1 tablespoon olive oil (optional)

Directions

Prep the veg and spinach: finely chop the onion and mince the garlic; thaw the frozen spinach in the microwave or cold water and squeeze it very dry so the filling won't be watery.
Sweat the onion and garlic: heat the olive oil in a small skillet over medium heat, cook the onion until soft and translucent about 4 minutes, add the garlic for 30 seconds just to smell it, then let cool a bit.
Make the filling: in a bowl combine the ricotta, drained chopped spinach, the cooked onion and garlic, 1 cup of the shredded mozzarella, the grated Parmesan, the egg, Italian seasoning, salt and pepper, and most of the chopped parsley (save a little for garnish). Mix until evenly combined, taste and adjust salt if needed.
Pour a little sauce in the slow cooker: spread about 3/4 cup of the marinara on the bottom of a 6 to 7 quart slow cooker so the shells won't stick.
Stuff the shells: using a teaspoon or small spoon, fill each uncooked jumbo shell with the ricotta-spinach mixture (don't mound it too high or they won't sit right), then place them seam side up in a single snug layer in the slow cooker.
Add remaining sauce and cheese: spoon the rest of the marinara over the arranged shells ensuring most tops are covered; if your sauce is very thick add up to 1/2 cup water to help the pasta cook. Sprinkle the remaining mozzarella evenly over the top and a little extra Parmesan if you like.
Cook: cover and cook on LOW for 2 1/2 to 3 hours or on HIGH for 1 1/2 to 2 hours, until the shells are tender and the filling feels set and the cheese is bubbly. Times vary by slow cooker so check at the lower end of the range.
Rest before serving: turn off the slow cooker and let the dish sit covered for 10 to 15 minutes so it firms up and is easier to serve.
Serve and finish: garnish with the remaining fresh parsley, scoop out carefully with a spatula and serve with extra Parmesan and a simple salad. If any shells stuck a bit use a thin spatula to loosen them.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.