In a medium pot over medium heat, add 1 tablespoon vegetable oil. Add beef. Season with salt and pepper. Cook until mostly cooked through with a little pink. Transfer to a medium bowl and set aside. Wipe the pot dry with paper towel.
In the same pot over medium heat, add 1 tablespoon vegetable oil. Add onion and bell pepper. Cook until soft, about 5 minutes. Stir in curry paste, garlic and ginger, and cook for 1 minute. Pour in chicken broth and coconut milk. Scrap off any browned bits from the bottom of the pot. Bring to a boil and reduce to a simmer. Cook for 10 minutes.
Meanwhile, bring a medium pot of water to a boil. Cook the rice noodles according to package directions. Drain and transfer the noodles into 2 serving bowls.
Back to the broth. Add fish sauce and brown sugar. Cook for another 3 minutes. Add beef and kaffir lime leaves. Cook for 3 more minutes. Taste and adjust the seasoning. Remove from heat. Stir in green onions, cilantro and basil. Transfer to the serving bowls. Serve immediately. Squeeze in a couple drops of lime juice if desired.