Patty Melt

Bahan-bahan (2 porsi)

• ½ pound ground beef (divided)
• 1 teaspoon salt
• ½ teaspoon pepper
• 3 tablespoons butter
• ½ large onion (thinly sliced)
• 6 tablespoons water (divided)
• 4 slices rye bread (or your bread of choice)
• 4 slices swiss cheese
• 4 slices provolone cheese (or your cheeses of choice)