16 oz. salmon, cooked and flaked (canned or homemade)
1/4 cup butter
1 cup button mushrooms, sliced
1/4 cup all-purpose flour
2 cups milk
2 cups green peas (fresh or frozen and thawed)
Kosher salt and fresh ground black pepper
2 cups cooked penne pasta
1 cup breadcrumbs
Lemon slices (optional)
Crème fraîche (optional)
Heat oven to 375 F.
Grease a large baking dish with butter or nonstick cooking spray and set aside.
In a medium saucepan, melt the butter over medium-high heat.
Add the mushrooms to the pan and cook until just brown, about 5 minutes.
Add flour to the saucepan, and cook until a nutty-brown paste, or roux, is formed, about 1 or 2 minutes. Remove the saucepan from the heat.
Slowly add the milk to the saucepan, whisking constantly, to combine the roux and milk.
Return saucepan to the heat, still whisking constantly, until bubbles start to form. Allow to simmer for 1 minute.
Add the peas, salmon, and and pepper to the saucepan.
Using a rubber spatula, fold the ingredients together until well-combined. Avoid breaking up the salmon too much.
Pour the salmon mixture over the bowl of cooked pasta, and stir gently to combine.
Transfer the salmon mixture into the prepared baking dish, and spread it evenly.
Sprinkle the breadcrumbs on top of the casserole.
Place the baking dish in the oven, and allow to cook until casserole is hot all the way through and the sides are browned and bubbling, about 30 minutes.
Remove casserole from the oven and allow to cool 3 to 5 minutes.
Serve directly from the baking dish using a spatula or ladle onto individual plates. Garnish with lemon slices or crème fraîche if you like.