Shrimp Mushroom Casserole

My sister-in-law brought this shrimp casserole to our first holiday potluck together, and I honestly could not stop going back for seconds. The way the creamy sauce hugged those tender shrimp while the panko topping added this perfect crunch was absolutely magical. Now it is my go-to when I want something that feels special but does not require hours of standing at the stove.

Last winter my neighbor came over for dinner when she was going through a tough time. I made this casserole with some crusty bread, and she actually asked for the recipe before she even finished her first serving. There is something about comfort food that just says everything will be okay.

Ingredients

• 450 g (1 lb) large shrimp: Peeled and deveined saves so much time and lets the shrimp really absorb that creamy sauce
• 250 g (8 oz) cremini or button mushrooms: Slice them evenly so they all get that gorgeous golden color when sautéing
• 1 small onion: Finely chopped so it melts into the sauce instead of being chunky
• 2 cloves garlic: Minced fresh because nothing replaces that aromatic punch
• 2 tablespoons chopped fresh parsley: Adds a bright pop of color and fresh flavor against all that richness
• 120 g (1/2 cup) sour cream: The secret ingredient that makes the sauce velvety and tangy
• 120 ml (1/2 cup) whole milk: Creates the perfect base without making things too heavy
• 60 g (1/2 cup) shredded mozzarella cheese: Gives those lovely melted strands throughout
• 30 g (1/4 cup) grated Parmesan cheese: Brings a salty umami depth that balances everything
• 2 tablespoons unsalted butter: Use this for greasing the pan and half in the skillet for flavor
• 2 tablespoons olive oil: Helps the vegetables caramelize beautifully without burning
• 2 tablespoons all-purpose flour: Just enough to thicken the sauce into something luscious
• 1 teaspoon paprika: Adds a subtle warmth and gorgeous color
• 1 teaspoon salt: Enhances all the flavors without overpowering
• 1/2 teaspoon black pepper: Freshly ground makes all the difference here
• 1/2 teaspoon dried thyme: Earthy and aromatic pairs perfectly with seafood
• 80 g (3/4 cup) panko breadcrumbs: Creates the most irresistible crispy golden topping
• 1 tablespoon melted butter: Toss this with the panko so it turns perfectly golden brown

Instructions

Get your oven ready:

Preheat to 190°C (375°F) and butter a 1.5 to 2 liter casserole dish so nothing sticks later

Sauté the aromatics:

Heat olive oil and 1 tablespoon butter in a large skillet over medium heat, cook the chopped onion for about 3 minutes until soft and translucent

Add the mushrooms:

Stir in sliced mushrooms and sauté for 5 minutes until they are golden and fragrant, then add garlic for just 1 minute so it does not burn

Build the sauce base:

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

Create the creamy sauce:

Pour in milk gradually while whisking to prevent any lumps, then add sour cream, paprika, salt, pepper, and thyme and simmer for 2 to 3 minutes until thickened

Add the shrimp:

Stir in shrimp and cook for just 2 minutes until they start turning pink because they will finish cooking in the oven

Assemble the casserole:

Fold in mozzarella, half the Parmesan, and parsley, then pour everything into your prepared dish

Make the crispy topping:

Mix panko with melted butter and remaining Parmesan, then sprinkle evenly over the entire surface

Bake to golden perfection:

Bake uncovered for 20 to 25 minutes until bubbling around the edges and beautifully browned on top

Let it rest:

Wait 5 minutes before serving so the sauce sets slightly and makes serving much easier

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My husband asked if we could have this every Friday night after I made it the first time. It has become that thing we look forward to all week, the kind of meal that makes the house smell incredible and brings everyone to the table.

Make Ahead Magic

You can assemble the entire casserole up to a day in advance and keep it covered in the refrigerator. Just add a few extra minutes to the baking time since it will be cold going into the oven.

Perfect Pairings

A crisp green salad with vinaigrette cuts through the richness perfectly. Steamed rice or crusty bread are both wonderful for soaking up every drop of that creamy sauce.

Wine Wisdom

Sauvignon Blanc brings bright acidity that complements the shrimp beautifully. Chardonnay works wonderfully too if you prefer something with a bit more buttery notes to match the dish.

• Serve the wine slightly chilled to refresh the palate between bites
• A light pinot grigio is another fantastic option
• Avoid heavy reds that will overpower the delicate seafood

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This casserole is one of those dishes that makes people feel truly special and cared for. I hope it becomes a beloved favorite in your home too.

Your Recipe Questions Answered

→ Can I use frozen shrimp?

Yes, thaw frozen shrimp completely and pat them dry before adding to the sauce. This prevents excess moisture from making the casserole watery.

→ How do I know when the shrimp are done?

The shrimp should turn pink and opaque. Since they continue cooking in the oven, remove them from the skillet when just beginning to turn color.

→ Can I prepare this ahead of time?

Assemble the casserole up to 24 hours in advance, cover tightly, and refrigerate. Add an extra 5-10 minutes to the baking time if baking cold from the refrigerator.

→ What can I substitute for the sour cream?

Greek yogurt or crème fraîche work well as substitutes. They provide similar tang and creaminess while maintaining the sauce's texture.

→ How should I store leftovers?

Store in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 160°C (325°F) until warmed through.

→ Can I make this gluten-free?

Replace the all-purpose flour with a 1:1 gluten-free flour blend and use gluten-free panko breadcrumbs for the topping.