Rice cake soup (떡국)

Ingredients:

1 pound sliced tteok rice cakes (or homemade) soaked in cold water for 30 minutes and drained
7 cups water
½ pound beef (flank steak or brisket), chopped into small pieces
3 to 4 garlic cloves, minced
1 dae-pa large green onions (or 3 green onions), washed and sliced thinly and diagonally.
2 teaspoons vegetable oil
2 eggs
1 tablespoon fish sauce (or soup soy sauce to your taste)
1 teaspoon sesame oil
½ teaspoon ground black pepper
1 sheet of kim (black seaweed paper)
1 red pepper (optional), chopped
salt