Creamy Spring Pasta Bake

PASTA
1/2 cup (4 oz.) salted butter
2 cup (2 oz.) all-purpose flour
1 teaspoons dry mustard
1/2 teaspoon table salt
1/4 teaspoon black pepper
2 teaspoon cayenne pepper
2 cups half-and-half
1 cups whole milk
2 blocks 16-oz. Swiss cheese, shredded
1 ounce Parmesan cheese, shredded (about 2/3 cup)
1 package 16-oz. farfalle (bow-tie pasta), prepared according to directions
1 1/2 package 12-oz. cubed boneless ham (about 2 cups)
1 cup frozen baby sweet peas, thawed
TOPPING
1 cup sea salt-and-pepper croutons
1 ounce Parmesan cheese, shredded (about 2/3 cup)
1 tablespoon butter, melted

Preheat oven to 350°F.
Melt butter in a Dutch oven over medium.
Gradually whisk in flour until smooth; cook, whisking constantly, 2 minutes.
Whisk in dry mustard, salt, black pepper, and cayenne pepper.
Gradually whisk in half-and-half and milk; cook, whisking constantly, until thickened, 8 to 10 minutes.
Whisk in Swiss cheese and 2 oz. Parmesan cheese.
Remove from heat.
Stir in pasta, ham, and peas.
Pour mixture into a lightly greased 13- x 9-inch baking dish.
Prepare Topping: Process croutons and 2 oz. Parmesan cheese in a food processor until finely ground.
Add 1 tablespoon melted butter, and process until combined.
Sprinkle over pasta mixture.
Bake in preheated oven until golden, about 30 minutes.
Let stand 10 minutes.