First marinate the beef. Combine the beef with the garlic, ginger, fish sauce, five-spice powder, and brown sugar until each piece is evenly coated. Marinate for 30 minutes.
Next, heat 3 tablespoons of oil in a large stock pot or Dutch oven over high heat. Add the stalks of lemongrass and allow them to infuse the oil for 1 minute. Next, add the minced lemongrass and garlic. Cook for 2 minutes.
Add the onions and cook until translucent. Then add all of the beef to the pot, and brown evenly on all sides. Add the tomato paste.
Stir and cook uncovered for 5 minutes. Add the water, coconut water, star anise, ground black pepper, chili powder, annatto, and paprika. Bring the mixture to a boil, reduce the heat to medium low, and simmer for 1 hour.
After an hour has passed, add the carrots, salt, soy sauce, and chili oil. Simmer for another 40 minutes.
To serve, remove the large lemongrass stalks and any star anise pods you can fish out. Cook your noodles per package instructions, transfer to bowls, and ladle the soup over the top.
Garnish with cilantro, Thai basil, and raw onion, and serve with some lime wedges on the side.