Colombian Milk and Egg Soup

Name: Colombian Milk and Egg Soup
Cuisine: American, Latin American
Ingredients: 4 cups whole milk; 2 cups water; 4 large eggs; 4 green onions, finely chopped (reserve the green tops for garnish); 1 clove garlic, minced; 1 small bunch cilantro, finely chopped (plus extra for garnish); 1 tsp salt (adjust to taste); 1 tsp ground black pepper; 4 slices of stale bread or toast (optional, for serving); Butter for toasting bread (optional)