To make the sauce:

Mix the palm sugar, tamarind paste, fish sauce, and chili powder together. Heat in a saucepan until warm and the palm sugar dissolves. Set aside. (If you want to store the sauce for several days, bring it to a boil and keep it in an airtight container.)

For the stir-fry: Heat vegetable oil in a wok. When hot, add the shrimp and stir-fry until they start to turn pink. Remove and set aside.

Add the tofu to the same wok and stir-fry until golden and fragrant. Add the chopped preserved radish and stir to combine. Pour in the prepared Pad Thai sauce and stir until it starts to simmer.

Add the soaked rice noodles and gently stir to combine. Push the noodles to one side of the wok.

Crack the egg into the empty side of the wok and scramble lightly. When the egg starts to set, mix it with the noodles. Add the cooked shrimp back in, then transfer everything to a plate. Serve with fresh bean sprouts, crushed roasted peanuts, extra chili powder, and lime wedges.