Slice the top sirloin as thin as possible. Marinate with the fish sauce and olive oil.
In a large sauce pan, reduce 3/4 cup of coconut milk over medium high heat for 5 minutes.
Stir in the curry paste, reducing the heat to medium low and cooking for a couple of minutes.
Stir in the lime leaves and palm sugar. Simmer until the palm sugar is dissolved.
Add in the top sirloin, making sure that the slices of beef are separated as much as possible. Cook until the beef is about half way cooked through.
Stir in the rest of the coconut milk. Cook for 1 more minute.
Stir in the Thai chilies. Turn off the heat.
Serve with steamed jasmine rice.