Pre heat oven to 400. Grease a 1 1/2 -2 quart casserole dish with non stick or butter. Cook potatoes until slightly softened about 8 min.then drain well. They will finish cooking in the oven. While potatoes are cooking , chop onion set aside. Mix together 2 tablespoons flour with gr. mustard, parsley, and seasoning blend. (I used garlic herb) in a small bowl. In a micro safe bowl, or small pan, whisk together milk and the other 2 1/2 tablespoons of flour and season blend, and heat to just warm. Layer in casserole dish potatoes, onion ,ham, flour and cheese until all used, ending with cheese on top. Pour warmed milk mixture over the top. Bake for 30 - 35 min or until cheese is brown and potatoes are bubbly. Let sit 5 -10 minutes before serving.