DIRECTIONS
Preheat oven to 400 degrees.
Pour milk into a large skillet over medium heat,
Place fillets into the milk.
Bring to a simmer; cook the fish 1 minute.
Transfer fillets to a plate and pour milk into a large measuring cup.
Fill a large pot with lightly salted water and bring to a boil.
Stir in the spinach fettuccine, bring back to a boil; cook pasta about 8 minutes; drain and transfer into a 2 quart casserole.
Toss with 1 TBSP. butter.
Melt remaining 3 TBSP. butter in skillet over medium heat and wisk flour into butter, stirring constantly until mixture forms a paste; cook and stir 1 minute, then whisk reserved milk and chicken stock into flour mixture until thoroughly combined.
Bring to a simmer, reduce heat to low and simmer until sauce has thickened, stirring often.
Remove sauce from heat; whisk in Dijon mustard, black pepper, nutmeg, 1/4 cup Parmesan cheese and Gruyere cheese.
Spread spinach over fettuccine noodles; arrange fillets on top of spinach.
Pour sauce over the fish and sprinkle remaining Parmesan and Gruyere cheese over the top.
Bake in preheated oven until sauce is bubbling, about 15 minutes.
Heat the oven’s broiler and broil until cheese topping is browned, 1 to 2 minutes.
Serves 4.