Shrimp Mushroom Casserole

The first time I made this shrimp mushroom casserole, my kitchen filled with such incredible aromas that my neighbor actually knocked on the door to ask what I was cooking. That's when I knew this recipe was something special. It's become my go-to when I want comfort food that still feels elegant enough for company.

Last winter, my sister came over exhausted from work, and I made this casserole while she curled up on the couch. When it came out of the oven bubbling and golden, she perked up immediately, and we ended up sitting at the kitchen table talking for hours while the dish cooled on the counter.

Ingredients

• 450 g large shrimp: Fresh or frozen works, but thaw completely and pat dry to prevent watery sauce
• 250 g cremini mushrooms: These have more flavor than button mushrooms, and they hold their texture better when baked
• 1 small onion: Finely chopped so it melts into the sauce without overwhelming the delicate shrimp
• 2 cloves garlic: Minced fresh, not jarred, for that sweet aromatic backbone
• 120 g sour cream: Full fat is best here, it creates such a luxurious texture without separating
• 120 ml whole milk: The fat content matters for a velvety sauce that coats everything beautifully
• 60 g mozzarella: Shredded from a block melts better than pre-shredded, which has anti-caking agents
• 30 g Parmesan: Grated fine adds that salty umami punch that makes the whole dish sing
• 2 tablespoons butter: Unsalted lets you control the seasoning, plus one extra tablespoon for the pan
• 2 tablespoons olive oil: For sautéing the vegetables and building those flavor layers
• 2 tablespoons flour: Just enough to thicken the sauce into something luscious and creamy
• 1 teaspoon paprika: Adds subtle warmth and that gorgeous golden hue to the sauce
• 1 teaspoon salt: Adjust to your taste, but shrimp need proper seasoning to shine
• 1/2 teaspoon black pepper: Freshly cracked makes all the difference here
• 1/2 teaspoon dried thyme: Earthy and fragrant, it pairs perfectly with both mushrooms and seafood
• 80 g panko breadcrumbs: These lighter Japanese breadcrumbs create such a delicate, crispy topping
• 1 tablespoon melted butter: Tossed with the panko to help it achieve that perfect golden brown

Instructions

Preheat your oven:

Set it to 190°C and butter a 1.5 to 2 liter casserole dish while the oven warms up.

Sauté the aromatics:

Heat olive oil and 1 tablespoon butter in a large skillet over medium heat, cook the onion for 3 minutes until softened, then add mushrooms and sauté until golden, about 5 minutes.

Add the garlic:

Stir in the minced garlic and cook for just 1 minute until fragrant, taking care not to burn it.

Build the sauce base:

Sprinkle flour over the vegetables and stir constantly for 1 minute to cook out the raw flour taste.

Create the creamy sauce:

Gradually pour in milk while whisking vigorously, then add sour cream, paprika, salt, pepper, and thyme, simmering until thickened, about 2 to 3 minutes.

Add the shrimp:

Stir in the shrimp and cook for only 2 minutes until they just start turning pink, remembering they'll finish cooking in the oven.

Combine everything:

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

Make the topping:

Mix panko with melted butter and remaining Parmesan in a small bowl until combined, then sprinkle evenly over the casserole.

Bake until golden:

Bake uncovered for 20 to 25 minutes until the sauce is bubbling around the edges and the topping is deeply golden.

Rest before serving:

Let the casserole sit for 5 minutes so the sauce sets slightly, making it easier to serve.

Save

My husband claims this recipe saved our date night game. We used to go out to expensive seafood restaurants, but now we'll put on some music, pour wine, and make this casserole together instead. It's become our favorite Friday tradition.

Making It Ahead

You can assemble the entire casserole up to a day in advance, wrap it tightly, and refrigerate. Just add an extra 5 to 10 minutes to the baking time since it will be cold. The topping actually gets even crispier when baked from chilled.

Cheese Variations

While mozzarella creates those gorgeous cheese pulls, Swiss or Gruyère add a nutty depth that's incredible with the mushrooms. I've even used sharp cheddar when that's what I had in the fridge, and it still turned out wonderfully comforting.

Serving Suggestions

A crisp green salad with bright vinaigrette cuts through the richness perfectly, though steamed rice soaks up that creamy sauce beautifully. I also love roasted asparagus or broccolini on the side for something green and fresh.

• Crusty bread is never a bad idea for catching every drop of sauce
• A light white wine like Sauvignon Blanc complements without overpowering
• Keep the lemon wedges on hand for a bright squeeze right before serving

Save

There's something so satisfying about pulling this bubbling dish from the oven and watching everyone gather around the table. Hope it brings your kitchen as much warmth as it's brought mine.

Recipe FAQs

→ Can I use frozen shrimp instead of fresh?

Yes, frozen shrimp work perfectly. Thaw them completely and pat dry before adding to prevent excess moisture in the sauce. Cooking time remains the same.

→ What other mushrooms can I use?

Cremini and button mushrooms are ideal, but you can substitute shiitake for a smokier flavor or use portobello for a meatier texture. Slice them evenly for consistent cooking.

→ Can I assemble this ahead of time?

Absolutely. Assemble the complete casserole, cover tightly, and refrigerate for up to 24 hours. Add the breadcrumb topping just before baking. You may need 5-10 extra minutes in the oven.

→ How do I know when the shrimp are done?

The shrimp will turn pink and opaque. Since they continue cooking in the oven, remove from the stovetop when just beginning to color. Overcooking makes them rubbery.

→ Can I make this gluten-free?

Yes. Replace the all-purpose flour with a 1:1 gluten-free flour blend and use gluten-free panko or crushed gluten-free crackers for the topping.

→ What sides pair well with this casserole?

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