INGREDIENTS
5 tbsp
unsalted butter
1
medium onion, finely chopped
1/4 cup
all-purpose flour
1/2 tsp
coarse salt
1 tsp
Italian Seasoning
1/2 tsp
black pepper
4 cups
whole milk
8 4/5 oz
mozzarella cheese + 1 cup, shredded
5 cups
thinly sliced peeled potatoes (about 6 medium potatoes)