Shrimp Mushroom Casserole

The first time I made this casserole, it was supposed to be a quick Tuesday dinner but ended up being the dish my sister still talks about three years later. I had forgotten to defrost anything else, and shrimp was the only protein that thawed fast enough for my hungry family. The creamy sauce came together so beautifully that my brother-in-law actually asked for seconds before anyone else had finished their first serving.

Last winter, during that terrible week when everyone in the house was sick, this casserole was the only thing that brought warmth back to our kitchen. The smell of mushrooms and butter wafting through the house somehow made everything feel manageable again. My daughter actually said she felt better just seeing it come out of the oven, bubbling and golden.

Ingredients

• 450 g (1 lb) large shrimp: Fresh shrimp gives the best results, but frozen works perfectly if you thaw them completely and pat them dry before cooking
• 250 g (8 oz) cremini or button mushrooms: Cremini mushrooms have a deeper, earthier flavor that stands up beautifully to the creamy sauce
• 1 small onion: Finely chopped so it virtually disappears into the sauce, providing sweetness without texture
• 2 cloves garlic: Minced fresh adds that aromatic kick that makes the whole kitchen smell incredible
• 2 tablespoons chopped fresh parsley: Brightens the rich flavors and adds a fresh pop of color to the finished dish
• 120 g (1/2 cup) sour cream: The secret to the silky sauce texture and gentle tanginess that balances the seafood
• 120 ml (1/2 cup) whole milk: Creates the perfect creamy base without making the sauce too heavy
• 60 g (1/2 cup) shredded mozzarella cheese: Melts into gooey pockets throughout the casserole
• 30 g (1/4 cup) grated Parmesan cheese: Adds that savory, salty depth that makes everything taste restaurant-quality
• 2 tablespoons unsalted butter: One tablespoon for sautéing vegetables, one for preparing the baking dish
• 2 tablespoons olive oil: Provides the foundation for building flavors in the pan
• 2 tablespoons all-purpose flour: Just enough to thicken the sauce into that perfect coating consistency
• 1 teaspoon paprika: Adds a subtle warmth and beautiful color to the creamy sauce
• 1 teaspoon salt: Enhances all the flavors without overwhelming the delicate shrimp
• 1/2 teaspoon black pepper: Freshly cracked gives the best aromatic punch
• 1/2 teaspoon dried thyme: Earthy and floral, this pairs perfectly with both mushrooms and seafood
• 80 g (3/4 cup) panko breadcrumbs: Creates that crispy, golden topping everyone reaches for first
• 1 tablespoon melted butter: Tossed with the panko to ensure the topping browns evenly and gets perfectly crisp

Instructions

Preheat your oven:

Heat the oven to 190°C (375°F) and butter a medium casserole dish, making sure to coat the sides well so nothing sticks.

Build the flavor base:

Heat olive oil and 1 tablespoon butter in a large skillet over medium heat, then add chopped onion and cook until softened, about 3 minutes.

Add the mushrooms:

Stir in the sliced mushrooms and sauté until golden brown, about 5 minutes, then add the garlic and cook for just 1 more minute until fragrant.

Make the roux:

Sprinkle the flour over the vegetables while stirring constantly to coat everything, and cook for 1 minute to remove the raw flour taste.

Create the creamy sauce:

Gradually pour in the milk while whisking constantly to prevent lumps, then add the sour cream, paprika, salt, pepper, and thyme, and simmer until thickened, about 2-3 minutes.

Add the shrimp:

Stir in the shrimp and cook just until they begin to turn pink, about 2 minutes, knowing they will finish cooking in the oven.

Combine everything:

Gently fold in the mozzarella, half the Parmesan, and parsley, then pour the mixture into your prepared casserole dish.

Prepare the topping:

In a small bowl, combine the panko, melted butter, and remaining Parmesan until well blended.

Top and bake:

Sprinkle the crumb mixture evenly over the casserole and bake uncovered for 20-25 minutes until bubbling around the edges and golden brown on top.

Rest before serving:

Let the casserole sit for 5 minutes before serving to allow the sauce to set slightly, making it easier to scoop.

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This recipe became our go-to for new neighbors and tough days at work. There is something about bubbling, cheesy seafood that makes people feel immediately at home, like they have been part of the family forever.

Choosing the Right Shrimp

I have learned through many failed attempts that shrimp size matters more than I ever thought possible. Large shrimp hold up better during baking and feel more luxurious in every bite, while smaller ones tend to disappear into the sauce. Fresh shrimp from the fish counter will always give you the best texture, but good quality frozen shrimp thawed properly work beautifully for weeknight meals when time is tight.

Making It Your Own

After making this casserole countless times, I have discovered that small changes can make it feel completely new. Sometimes I add a pinch of red pepper flakes when I want warmth, or swap in Gruyère cheese for a nuttier, more sophisticated flavor that works beautifully for dinner parties. The basic technique stays the same, but these little adjustments keep the recipe exciting and ensure it never feels repetitive.

Perfect Pairings

A crisp green salad with a vinaigrette cuts through the richness and adds a refreshing contrast to every bite. Steamed rice works wonderfully if you want to stretch the dish to feed more people, and the grains soak up that incredible sauce. For wine, a chilled Sauvignon Blanc or buttery Chardonnay complements the shrimp and mushrooms beautifully without overpowering them.

• Serve with crusty bread to mop up every last drop of the sauce
• Roasted asparagus or green beans make excellent spring sides
• Lemon wedges on the side let guests brighten their portions to taste

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There is nothing quite like pulling this golden bubbling dish out of the oven and watching everyone's faces light up. Hope it brings as much warmth to your table as it has to mine.

Recipe FAQs

→ Can I use frozen shrimp for this casserole?

Yes, frozen shrimp work perfectly. Thaw them completely and pat dry before adding to the sauce. Avoid overcooking since they'll finish baking in the oven.

→ What mushrooms work best in this casserole?

Cremini or button mushrooms are ideal for their earthy flavor and firm texture. Portobello mushrooms can be used for a meatier bite, while shiitakes add depth.

→ Can I prepare this casserole ahead of time?

Assemble the casserole up to 24 hours in advance, cover tightly, and refrigerate. Add the topping just before baking. You may need to extend baking time by 5-10 minutes.

→ What sides pair well with this dish?

A crisp green salad with vinaigrette balances the richness. Steamed rice, roasted vegetables, or crusty bread also complement the creamy sauce beautifully.

→ How do I store and reheat leftovers?

Refrigerate in an airtight container for up to 3 days. Reheat at 180°C (350°F) covered with foil for 15-20 minutes until heated through.

→ Can I make this gluten-free?

Substitute all-purpose flour with a 1:1 gluten-free flour blend and use gluten-free panko breadcrumbs. The flavor and texture remain excellent.