Prepare the Chicken - Cut the meat against the grain into strips, about ¼-inch thick and 2-inches long. Combine with salt and pepper. Set aside.
Cook the Noodles - Heat a large pot of water until it becomes lukewarm, about 80 to 90°F (27 to 32°C), then turn off the heat. Soak the rice noodles until flexible but not thoroughly cooked, al dente, about 5 to 10 minutes. If needed, slightly increase the heat to speed up the softening. Use a colander to drain and rinse with cold water.
Make the Sauce - In a medium bowl, whisk together the palm sugar, fish sauce, tamarind paste, lime juice, and rice vinegar. Set aside.
Sear the Chicken - Heat a large wok or saute pan over medium-high heat. Add the vegetable oil. Once hot and shimmering, carefully add the chicken in a single layer. Sear without moving until browned, about 30 seconds. Stir-fry until no longer pink, about 1 to 2 minutes, do not overcook! Push meat to the side of the pan.
Add the Garlic and Egg - Add the garlic and stir-fry for 15 seconds. Add the egg and quickly stir the yolk. Mix to scramble and break into smaller pieces.
Add the Noodles - Add in the soaked noodles and stir to combine. Cook for 2 minutes to soften and warm.
Add the Sauce and Seasonings - Add the sauce and stir to combine. Turn off the heat. Add the paprika (if using), and toss until the noodles turn slightly red. Add the green onions and allow them to wilt slightly.
To Serve - Transfer to a plate, garnish with bean sprouts and chopped peanuts, and serve with lime wedges.
Notes
Recipe Yield: 8 cups
Serving Size: About 1 cup
Sauce Yield: ¼ cup
Palm Sugar Substitute: Brown sugar, granulated sugar, coconut sugar, honey, or pure maple syrup.
Tamarind Paste Substitutes: Fruit jam, preserves, or marmalades like guava, strawberry, or orange. Tangy pomegranate molasses syrup. Dried fruit like apricots, dates, raisins, pineapples, and prunes soaked in warm water, drained and pureed into a paste. Balance the taste with lime juice and rice vinegar as needed.
For Saucier Noodles: Double the sauce for more of a coating on the noodles.
For a Spicier Sauce: Use hot paprika (reducing the amount of sweet paprika), sambal oelek, or Thai chili paste. Start with ¼ teaspoon and increase to the desired spice level.
More Protein: Use 16 ounces of chicken for a heartier dish.
Storing: Store in an airtight container in the refrigerator for up to 3 days.
Reheating: Cover and cook inside the microwave on the high setting in 15 to 30-second increments until hot. Reheat in a pan on the stovetop over medium heat, stirring until hot. If needed, add water, one tablespoon at a time to soften the noodles.