8 ounces medium egg noodles
4 tablespoons butter, divided
1 cup chopped onion
2 1/2 to 3 cups diced corned beef, about 12 ounces
16 ounces chopped frozen spinach, thawed, excess water squeezed out
3 tablespoons all-purpose flour
1 cup chicken broth
1 cup milk (low fat is fine)
1/8 teaspoon black pepper
1/4 teaspoon dried leaf thyme
2 cups shredded sharp Cheddar cheese
1/2 teaspoon salt, or to taste
1/2 to 1 cup French fried onion rings or buttered bread crumbs, optional
Using a large saucepan or stock pot, cook noodles following package directions; drain well.
Put noodles back in the pot and set aside.
In a medium saucepan, melt 2 tablespoons of butter over medium-low heat; cook onion for 2 minutes.
Add corned beef and cook until lightly browned.
With a slotted spoon, transfer beef mixture to the pot with noodles.
Add the squeezed spinach to the pot and set aside.
In the same medium saucepan, melt remaining 2 tablespoons butter over medium-low heat; stir in flour until well blended and bubbly.
Stir in chicken broth and milk.
Cook, stirring constantly, until thickened and bubbly.
Add pepper and thyme.
Stir in the cheese, cooking until melted.
Add salt to taste.
Pour sauce over the noodle and corned beef mixture; stir until well blended.
Spoon the noodle mixture into prepared baking pan.
If desired, top with crumbled french fried onion rings or buttered bread crumbs.
Bake for 30 minutes, or until hot and lightly browned.
Serves 4 to 6.