Croque Monsieur Mac and Cheese

INGREDIENTS

1/2 lb

ziti

2 cups

milk

2 cups

coarsely grated gruyere cheese (about 6 ounces)

1 cup

finely grated parmesan cheese (about 4 ounces)

large eggs

slices white sandwich bread, roughly diced

2 tbsp

unsalted butter, plus more for greasing

medium onion, diced

1 clove

garlic, minced

3 tbsp

all-purpose flour

cayenne pepper

1/8 tsp

freshly grated nutmeg

Kosher salt

8 oz

thinly sliced deli-boiled ham