Cook noodles of choice according to the package instructions.
In a large skillet over medium-high heat, warm 1 tablespoon oil. Add the beef and ½ teaspoon salt. Break into chunks and let cook undisturbed for about 3-5 minutes or until browned, then give it a stir and cook until cooked through, continuing to break into smaller chunks. Transfer to a plate. If a lot of oil remains, remove all but one tablespoon.
Add the remaining 1 tablespoon oil (or leave this out if there is enough oil from the beef in the pan), onion, carrots and remaining ½ teaspoon salt. Cook for 4-6 minutes, or until softened, stirring occasionally. Add the curry powder, fennel, turmeric, sesame oil, and red pepper flakes (if using) and cook for about 30 seconds to bloom the spices, stirring constantly (to prevent the spices from burning).
Immediately add the coconut milk, water, veggies (see recipe note), and soy sauce. Bring to a boil over high heat, then reduce to medium-low and simmer rapidly for about 10 minutes. Turn off the heat.
Stir in the cooked beef and lime.
Serve with noodles and top with plenty of herbs.