Oyster Casserole Recipe
A rich, savory oyster casserole featuring tender oysters, mushrooms, aromatic vegetables, and a seasoned cream sauce beneath a crisp, buttery breadcrumb topping.
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Ingredients
For the Oyster and Vegetable Mixture
- 2 lb shucked oysters thoroughly drained, with the liquid reserved
- 8 oz white mushrooms sliced
- 1 cup green bell pepper cut into small dice
- 2 scallions thinly sliced
- 2 tbsp unsalted butter
- 1 large onion finely chopped
- 2 garlic cloves minced
- 1 cup celery diced into small, evenly sized pieces
For the Cream Sauce
- 1 cup half-and-half or whole milk for a lighter consistency
- 1 tbsp Worcestershire sauce
- 3/4 tsp kosher salt
- 2 tbsp all-purpose flour generously measured
- 1 tbsp fresh lemon juice
- 1/2 tsp ground black pepper
- 1 tbsp hot sauce
- 2 tbsp unsalted butter for preparing the roux
For the Breadcrumb Topping
- Melted butter as needed to coat the crumbs
- 1 cup breadcrumbs preferably prepared from the soft interior of a day-old French baguette
- Pinch of salt
Instructions
- Set the oven to 400°F (200°C). Drain the shucked oysters, rinse them with water, and place them in a bowl until needed.
- Melt 2 tablespoons of unsalted butter in a large skillet over medium heat. Add the finely chopped onion, diced celery, and green bell pepper. Cook for 4–5 minutes, or until the vegetables have softened.
- Stir in the sliced scallions and minced garlic. Continue cooking for approximately 1 minute, just until the garlic becomes aromatic.
- Add the sliced white mushrooms and prepared oysters to the skillet, stirring them into the vegetable mixture. Cook for approximately 15 minutes, allowing the oysters and mushrooms to release their moisture.
- Position a colander over a bowl and carefully pour the skillet mixture into it. Allow the excess liquid to drain away.
- In a separate saucepan, melt 2 tablespoons of unsalted butter over medium heat. Add the flour and stir continuously for approximately 1 minute, until the roux develops a texture resembling damp sand.
- Slowly pour in the half-and-half while stirring steadily to produce a smooth, lump-free sauce.
- Add the lemon juice, Worcestershire sauce, hot sauce, kosher salt, and black pepper. Continue stirring for 2–5 minutes, or until the sauce has noticeably thickened.
- Return the drained oyster, mushroom, and vegetable mixture to the skillet and incorporate the prepared cream sauce, stirring until everything is evenly coated.
- Pulse the interior of a French baguette in a food processor until fine breadcrumbs form. Toss 1 cup of the crumbs with enough melted butter to lightly coat them, then season with a small pinch of salt.
- Transfer the creamy oyster mixture to a baking dish and distribute the buttered breadcrumbs evenly across the surface.
- Bake at 400°F (200°C) for approximately 15 minutes, or until the filling is hot and bubbling.
- For additional browning and crunch, place the casserole beneath a broiler set to high for 1–2 minutes. Watch carefully during this stage so the breadcrumb topping does not burn.
- Remove the casserole from the oven and allow it to cool briefly before serving.
Notes
Day-old baguette crumbs provide a particularly crisp, textured topping. Whole milk may be used in place of half-and-half when a lighter cream sauce is preferred.