In a small bowl, combine the brown sugar, tamarind concentrate, miso paste, soy sauce and 60ml (1/4 cup) of water. Whisk until all ingredients are completely incorporated. Set aside for later.

Cook your rice noodles according to the package's instructions. Set aside for later.

Over medium-high heat, add 15ml (one tablespoon) of neutral oil to a large nonstick skillet, add the tofu and cook on all sides until lightly golden brown and crisp, about five to ten minutes.

Increase the heat to high and add a bit more oil if needed to the pan. Once shimmering, add the whites of the green onions and the garlic. Cook until the garlic just begins to turn golden brown, about one minute. Add the chilis and cook for another thirty seconds.

Crack in the eggs, if using, and break them up with your spatula. Combine them with the onion, garlic and chili and cook until they're completely cooked through, only about thirty seconds to one minute.

Add the rice noodles and tofu to the pan. Pour over the pad thai sauce and, using tongs, toss until the sauce is mostly absorbed into the noodles and everything is well-combined - about a minute.

Turn off the heat and add the bean sprouts, peanuts, cilantro and green part of the green onions. Toss to combine.