Ingredients:
olive oil, for greasing the baking dish: 1 tablespoon
unsalted butter: 4 tablespoons
all-purpose flour: 4 tablespoons
milk: 3 cups
salt: ¾ tsp
pepper: ½ tsp
nutmeg: ¼ tsp
frozen peas: 1 cup
no-boil lasagna: 1 box
ricotta cheese: 1 16-ounce container
mozzarella cheese, shredded: 1½ cups
grated parmesan cheese: ½ cup