Bring a large pot of water to a boil. Remove from heat and add rice noodles. Soak noodles, stirrring occasionally, 5-7 minutes (until pliable).
Prepare sauce by combining brown sugar, fish sauce, rice wine vinegar, soy sayce, and lime juice in a small mixing bowl. Whisk well; set aside.
Cut tofu into bite sized pieces.
Heat 2 Tbsp. vegetable oil over medium-high heat in a large skillet or wok. Saute tofu until browned on both sides, about 10 minutes. Remove from pan.
Heat remaining 1 Tbsp. oil; add eggs to skillet and scramble them into small pieces.
Add softened noodles, bean sprouts, shredded carrots, green onions, tofu, and 1/2 c. peanuts to the skillet.
Add sauce and heat through, stirring occasionally, until sauce is absorbed.
Garnish with additional chopped peanuts, cilantro, and red pepper flakes.