Shrimp Mushroom Casserole

The first time I made this casserole, it was supposed to be a quick Tuesday dinner, but my roommate kept wandering into the kitchen asking what smelled so incredible. That buttery breadcrumb topping gets this incredible golden crunch that somehow makes everything underneath taste even richer.

Ive started making this for dinner parties because people assume it took hours to develop such complex flavors. Last month my friend actually asked for the recipe before shed even finished her first serving, which I consider the highest possible compliment.

Ingredients

• Large shrimp: Fresh shrimp works best here since theyre the star, but frozen and thawed is perfectly fine if you pat them really dry first
• Cremini or button mushrooms: These get such a beautiful golden color when sautéed, and that earthiness balances the rich cream sauce perfectly
• Onion and garlic: The foundation of flavor, minced small so they melt into the sauce without any chunky bits
• Sour cream and whole milk: This combination creates the most velvety sauce without being too heavy
• Mozzarella and Parmesan: Mozzarella brings that gorgeous melt while Parmesan adds the salty depth that makes you want just one more bite
• Butter and olive oil: Butter for flavor, olive oil so it doesnt burn, classic combination that never fails
• Flour: Just enough to thicken the sauce into something luscious that coats every shrimp and mushroom
• Paprika, thyme, salt and pepper: Paprika gives a subtle warmth, thyme brings that herbal brightness, and enough seasoning to make everything sing
• Panko breadcrumbs: These create the most incredible crispy topping that stays crunchy even under the creamy sauce

Instructions

Get your oven ready:

Preheat to 190°C (375°F) and butter your casserole dish, getting into all the corners so nothing sticks later

Build the flavor base:

Heat olive oil with one tablespoon butter in a large skillet, cook the onion until soft and translucent, then add mushrooms until they turn golden and smell wonderful

Add the aromatics:

Stir in garlic for just one minute, then sprinkle flour over everything and cook while stirring constantly to remove that raw flour taste

Create the creamy sauce:

Slowly pour in milk while whisking, add sour cream and all the seasonings, then let it simmer until thickened enough to coat the back of a spoon

Add the shrimp:

Gently stir in shrimp and cook just until they start turning pink, they should still be slightly undercooked since theyll finish in the oven

Assemble everything:

Fold in mozzarella, half the Parmesan, and parsley, then pour it all into your prepared baking dish

Make the golden topping:

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

Bake until bubbly:

Bake for 20-25 minutes until you see golden brown spots and the sauce is bubbling up around the edges

Let it rest:

Wait 5 minutes before serving, this helps the sauce set slightly so each spoonful holds together beautifully

Save

This dish has become my go to when I want something that feels special but doesnt require restaurant level skills. Watching people take that first bite and immediately relax into their chairs is the best part of making it.

Making It Your Own

Sometimes I swap in Swiss or Gruyère instead of mozzarella when I want something more sophisticated. The way those cheeses melt and brown on top creates this incredible crust that people fight over.

Perfect Pairings

A crisp green salad with bright vinaigrette cuts through the richness beautifully. I also love serving this with steamed rice to soak up every drop of that sauce.

Wine Wisdom

Sauvignon Blanc brings the perfect acidity to balance the cream, while a buttery Chardonnay complements those golden breadcrumbs. Either way, pour yourself a glass while it bakes.

• Add red pepper flakes if you like a little heat
• Fresh thyme beats dried by a mile if you have it
• The topping can be made ahead and kept in the fridge

Save

Theres something so comforting about a bubbling casserole coming out of the oven. I hope this becomes one of those recipes you turn to again and again.

Recipe FAQs

→ Can I use frozen shrimp for this casserole?

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

→ What type of mushrooms work best?

Cremini or button mushrooms are ideal for their earthy flavor and ability to hold texture during baking. Portobello slices can also work for a meatier bite.

→ Can I assemble this ahead of time?

Absolutely. Prepare everything up to step 7, cover tightly, and refrigerate for up to 24 hours. Add the topping just before baking and increase baking time by 5-10 minutes if baking cold.

→ How do I know when the shrimp are fully cooked?

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

→ What can I serve with this casserole?

A crisp green salad with vinaigrette cuts through the richness beautifully. Steamed rice, roasted vegetables, or crusty bread also make excellent sides. A chilled white wine like Sauvignon Blanc complements the flavors perfectly.

→ Can I make this gluten-free?

Yes. Substitute the all-purpose flour with a 1:1 gluten-free flour blend and use gluten-free panko breadcrumbs. The rest of the ingredients are naturally gluten-free.