In a large skillet, stir together hash, onion and mustard. Cook over medium heat
or medium-hot coals, stirring occasionally, until lightly browned, about 4 minutes.
With a spoon, make 8 indentations in hash mixture, about 2 inches in diameter
each. Break and drop an egg into each indentation. Cover and cook until egg whites
are almost set, about 10 - 15 minutes.
Cut each cheese slice into 4 triangles. Uncover hash and eggs; top with cheese
triangles in pinwheel fashion. Cover; remove from heat and let stand until whites
are set and cheese is melted, about 2 -3 minutes.