12 oz egg noodles
1/4 cup unsalted butter
2 cups sliced shallots or thinly sliced onions
2 cups diced celery
1/4 cup all-purpose flour
1/3 cup dry vermouth or dry white wine
1 1/2 cups of milk
1/4 cup cream
2 cups chicken or turkey stock
2 teaspoons dry tarragon
2 Tbsp whole grain mustard
3 cups coarsely chopped cooked turkey
6 ounces grated Gruyere cheese
1/2 teaspoon freshly ground black pepper
2 Tbsp lemon juice
1/2 cup panko bread crumbs
1 Tbsp melted butter
Freshly chopped parsley for garnish (optional)
Preheat oven to 375°F. Start heating 4 quarts of water for the pasta. Add 2 tablespoons of salt to the water (1 Tbsp for every 2 quarts of water).
Melt butter in a large, thick-bottomed pot (5-quart) on medium heat. Add the shallots and celery and cook until softened, about 5 minutes. Stir in the flour and cook over low heat, stirring for about 3 minutes.
Put the noodles into the boiling water you’ve heated. Follow the package directions and cook the noodles for 2 minutes less than the range given on the package. The pasta should be a bit firmer than al dente. So, for example, if the package instructions say bring to a boil and cook for 6 to 10 minutes, add the pasta to the hot water, return the water to a boil and cook it for 4 minutes. While the pasta is cooking continue on with the recipe.
Into the saucepan with the butter, shallots, celery, and flour, add the dry vermouth and let bubble for a minute. Then stir in the milk, cream, and stock. Add the tarragon. Bring to a simmer and cook over medium-low heat, stirring frequently, for about 5 to 8 minutes.
During this time the pasta will be ready. Drain it and rinse it with cold water to stop the cooking.
Add the grated cheese and mustard to the pot. Stir until the cheese is melted. Add the chopped cooked turkey to the pot. Add salt to taste (depending on if you are using salted stock or not, or salted butter or not, that could be no added salt to as much as a teaspoon). Add freshly ground black pepper.
Now it’s time to add the cooked pasta to the pot. If the noodles have stuck together, rinse them in the colander with a little water to separate the noodles from each other. Add the noodles to the pot with the turkey. Stir in the lemon juice. Adjust seasonings to your taste. Transfer the mixture to a buttered 3-quart casserole.
Sprinkle with panko and drizzle 1 Tbsp melted butter over the top.
Bake the casserole in the middle rack of the oven for 30 to 40 minutes, or until it is bubbling and the top is golden.
Garnish with chopped parsley, if using.