In a large mixing bowl, beat eggs, milk, salt, and pepper together until well blended. Melt butter in skillet over medium-low heat until hot; pour in egg mixture. Reduce heat. As mixture begins to set on bottom and sides of skillet, lift and fold over with spatula. Cook until eggs are almost set; spread honey mustard on slices of bread, top with sliced tomato, green onion and cooked scrambled eggs. Serves 4.