Make the Thai Tea: Bring 2 cups of water to a boil. Remove from heat and add the Thai tea mix (or black tea). Let it steep for about 5 minutes. Strain into a pitcher and stir in granulated sugar until dissolved. Chill in the refrigerator.

Marinate the Beef: Add all ingredients for the chashu beef into a bowl, then submerge the beef in the liquid. Cover with a lid and let it marinate while you prepare the other components.

Prepare the Broth: Preheat an oiled pot to medium-low heat. Sauté the onion, garlic, and ginger for 5 minutes, stirring often.

Add mushrooms, leeks, scallions, and broth to the pot. Ensure vegetables are covered by about 2 inches (5 cm) of broth.

Bring to a rolling boil over high heat, then reduce to a mild simmer. Cover the pot with a lid.

Add the marinated beef to the pot and continue simmering until the liquid reduces by about half.

Cook the Eggs (if using): Gently place eggs into the simmering broth and cook for about 6 minutes. Remove and place into an ice bath for a few minutes, then peel.

Cook the Noodles: Add ramen noodles to the simmering broth and cook according to package instructions.

Assemble: Portion broth into bowls. Add the noodles and top with slices of chashu beef and chopped scallions. Slice each egg in half lengthwise and place two halves per portion.

Serve with chilled Thai tea. Enjoy!