Morton's Steakhouse Creamed Spinach (Copycat)

INGREDIENTS

4 tbsp

unsalted butter

medium yellow onion, minced

3 cloves

garlic, minced

4 tsp

Kosher salt, divided

1 tsp

freshly ground black pepper

1/2 tsp

freshly grated nutmeg

1/4 cup

all-purpose flour

3 1/2 cups

half-and-half

2 1/4 lb

fresh leaf spinach (or one pound frozen)

1 cup

mozzarella cheese*

4 oz

cream cheese*

1/2 cup

grated Parmesan cheese