Preheat oven to 350°F. Preheat frying oil to 365°F.
Wash, peel and slice all of your root vegetables. Arrange in the bottom of a large baking dish with leftover ham. Set aside and prepare your cheese sauce.
In a medium saucepan, melt butter with your garlic over medium heat, whisk in 4 tablespoons of flour and form a paste.
Quickly whisk in 2 cups of milk until smooth. Heat until it comes to a low boil.
Fold in shredded cheeses and cream cheese, mix until smooth. Salt and pepper cheese sauce to taste. Pour over the top of your casserole.
To prepare onions, toss thin slices in flour and evenly coat. Fry one small handful at a time until crisp. Remove from oil and set onions on paper towels to drain off excess oil. Lightly salt.
Top casserole with onions and bake for about 35 minutes or until vegetable slices are fork tender.
Top with sliced scallions before serving.
Copyright Carrie Burrill, Bakeaholic Mama