Stuffed Shells with Ricotta, Spinach, and Portobello Mushrooms
Comforting, cheesy, and packed with savory vegetables, this Stuffed Shells with Ricotta, Spinach, and Portobello Mushrooms recipe is a weeknight winner and an impressive dish for company. Large pasta shells cradle a creamy ricotta filling studded with sautéed portobello mushroom, onion, garlic, red pepper, and tender spinach. A blanket of marinara and melted cheeses turns individual bites into warm, hearty spoonfuls of satisfaction.
This version uses simple pantry staples and swaps nothing essential, keeping the ingredient amounts straightforward so you can assemble everything quickly. The flavors are familiar but brightened by a dash of crushed red pepper and fragrant dried basil. Follow the recipe as written for reliably gooey, well-seasoned stuffed shells that reheat beautifully.
Why you’ll love these stuffed shells
- Make-ahead friendly: Assemble and refrigerate or freeze before baking.
- Vegetable-forward: Portobello mushrooms, red pepper, onion, garlic, and spinach add texture and depth.
- Cheesy comfort: Ricotta, mozzarella, and Parmesan create a luscious, melty filling.
- Simple pantry ingredients: Uses marinara sauce and jumbo shells you likely already have or can grab easily.
Ingredients
- 1 T olive oil
- 1 large portobello mushroom, chopped
- 1/2 onion, diced
- 3 cloves garlic, minced
- 1 red pepper, diced
- 1 15 oz ricotta cheese – I used low fat
- 1 egg
- 3/4 cup mozzarella cheese, shredded (divided)
- 1/2 cup Parmesan cheese, grated (divided)
- 1/2 cup frozen spinach, thawed, drained, and chopped (use a potato ricer to get rid of the water)
- 1/2 tsp dried basil
- Dash of crushed red pepper
- Salt and pepper
- About 3 cups of marinara sauce (I made my own, you can use store bought)
- About 18 jumbo pasta shells, cooked al dente, read box instructions 🙂
Equipment
- Large skillet
- Large pot for boiling pasta
- Colander and slotted spoon
- Mixing bowl
- 9×13 or similar baking dish
- Spoon for stuffing shells
- Potato ricer or clean dish towel for squeezing spinach
Step-by-step instructions
Follow these clear steps to build, fill, and bake the shells. Keep ingredient amounts the same as listed above.
- Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish and set it aside.
- Bring a large pot of salted water to a boil. Add the jumbo pasta shells and cook them until they are al dente according to the box instructions. Use a slotted spoon to transfer the shells to a sheet pan or plate lined with a clean kitchen towel to cool slightly and prevent sticking. Reserve a cup of the pasta water if you want to thin the sauce later.
- While the pasta cooks, heat 1 T olive oil in a large skillet over medium heat. Add the diced onion and sauté for 3–4 minutes until it begins to soften.
- Add the chopped portobello mushroom to the skillet and continue cooking for another 4–5 minutes, stirring occasionally, until the mushroom releases its moisture and starts to brown.
- Add the minced garlic and diced red pepper to the skillet. Sauté for 2–3 minutes more until the garlic is fragrant and the pepper softens. Season the mixture with a pinch of salt and pepper. Remove the skillet from the heat and let the vegetables cool slightly.
- In a large mixing bowl, combine the 15 oz ricotta cheese, 1 egg, 1/2 cup of the shredded mozzarella, 1/4 cup of the grated Parmesan, 1/2 cup of the drained and chopped spinach, 1/2 tsp dried basil, a dash of crushed red pepper, and a pinch of salt and pepper. Stir until the mixture is smooth and evenly mixed.
- Fold the cooled sautéed vegetables into the ricotta mixture until distributed evenly. Taste and adjust seasoning with additional salt, pepper, or red pepper flakes if desired.
- Spoon about 1/2 cup of marinara sauce into the bottom of the prepared baking dish and spread it into an even layer.
- Using a small spoon, carefully fill each cooked jumbo shell with the ricotta and vegetable filling. Arrange the stuffed shells seam-side up in the baking dish on top of the sauce. Continue until you have filled and placed about 18 shells (or as many as fit snugly in your dish).
- Pour the remaining marinara sauce evenly over the shells so they are mostly covered. If the dish looks dry, add a little reserved pasta water to loosen the sauce.
- Sprinkle the remaining 1/2 cup mozzarella and 1/4 cup grated Parmesan evenly over the top of the sauced shells.
- Cover the baking dish loosely with foil and bake in the preheated oven for 20 minutes. Remove the foil and bake an additional 10 minutes, or until the cheese is melted and bubbly and the edges show a bit of golden color.
- Let the baked shells rest for 5 minutes before serving. Garnish with extra grated Parmesan or a pinch of dried basil if you like. Serve hot with a crisp green salad or garlic bread.
Make-ahead and storage
- To make ahead: Assemble the stuffed shells in the baking dish, cover tightly with plastic wrap, and refrigerate for up to 24 hours. Bake as directed, adding a few extra minutes if starting from chilled.
- To freeze: Assemble the shells in a freezer-safe dish, cover with foil, and freeze for up to 3 months. Bake from frozen at 375°F (190°C) covered for about 45–55 minutes, then uncover and bake until reheated through and cheese is bubbly.
- Leftovers: Store in an airtight container in the refrigerator for up to 3 days. Reheat in the oven at 350°F until warmed through, or microwave individual portions.
Troubleshooting tips
- If the filling seems watery: Make sure your spinach is very well drained—use a potato ricer or squeeze firmly in a towel. Also, allow the sautéed mushrooms to cool so any excess liquid can settle and be left behind in the pan.
- If shells split while stuffing: Don’t overstuff them. A heaping teaspoon to tablespoon per shell is usually enough; handle gently when placing them in the dish.
- If the top browns too quickly: Tent with foil during the last 5–10 minutes of baking to prevent over-browning while the inside finishes heating.
Serving suggestions
Serve these Stuffed Shells with Ricotta, Spinach, and Portobello Mushrooms with a crisp green salad, steamed broccoli, or a basket of crusty bread to mop up the sauce. A simple side of sautéed greens or roasted vegetables pairs nicely for a balanced meal.
Enjoy the cozy, cheesy satisfaction of these stuffed shells. They’re a great way to get more vegetables on the table without sacrificing any comfort-factor—and they make a comforting weeknight dinner that doubles as a crowd-pleasing dish for gatherings.
Stuffed Shells with Ricotta, Spinach, and Portobello Mushrooms
Creamy ricotta and spinach-stuffed jumbo shells with sautéed portobello and marinara make a comforting, family-friendly casserole.
Ingredients
Equipment
Method
- Preheat the oven to 350°F (175°C) and spray a 9x13-inch baking dish with cooking spray.
- Heat the olive oil in a large skillet over medium heat. Add the diced onion and cook until softened, about 4–5 minutes.
- Add the minced garlic, chopped portobello, and diced red pepper to the skillet; sauté until the vegetables are tender, about 4–6 minutes. Remove from heat and let cool slightly.
- In a large bowl, combine the ricotta, 1/4 cup of the shredded mozzarella, and 1/4 cup of the grated Parmesan. Stir in the egg, drained chopped spinach, dried basil, crushed red pepper, salt, and black pepper until creamy.
- Fold the cooled mushroom, onion, and red pepper mixture into the ricotta mixture until evenly combined.
- Spread 1/2 cup of marinara sauce over the bottom of the prepared baking dish.
- Place the cooked jumbo shells in the dish in a single layer and spoon the ricotta mixture into each shell, spacing them evenly.
- Pour the remaining marinara sauce over the stuffed shells, then sprinkle the remaining mozzarella and Parmesan over the top.
- Cover the dish with foil and bake for 30 minutes. Remove the foil and bake an additional 5 minutes until bubbling and cheese is melted.
- Let the casserole rest for a few minutes before serving warm.
Notes
- Drain spinach thoroughly using a potato ricer or squeeze in a towel.
- Cook shells just to al dente so they hold shape when stuffed.
- You can use store-bought marinara for convenience.
- Allow the dish to rest a few minutes before serving.
