Boil eggs for 10 minutes. After water comes to a boil, immediately crack them and run them under cold water. This makes peeling them much easier. Once peeled, cut and separate them as you would if you were preparing deviled eggs. Chop the egg whites in half, and then into smaller pieces. When the yolks have cooled a bit, use a grater or mash them with a fork until they become crumbly. In the meantime make your roux (white sauce) by adding butter and flour in a double boiler setting the burner on high. Slowly add milk and whisk continuously after each addition of milk becomes thickened. Continue this process on medium high heat until you have used just between 1 and 2 C. milk, or until smooth and somewhat thick. Add your chopped egg whites and seasonings to taste. Toast your 4 slices of bread. Pour your sauce into a casserole dish and sprinkle all of the egg yolks evenly over the sauce mixture. Garnish with paprika and parsley as you wish.