Heat up olive oil or sesame oil over medium high heat and start browning your strips of flank steak. Make sure both sides are browned. About 3 minutes per side.
Remove meat and set aside.
Add onions and red bell pepper and saute until the onions are translucent, about 8 minutes.
Add garlic, ginger, coriander, cinnamon, and salt. Combine well and saute for a few minutes until fragrant
Add coconut milk, sugar, curry powder, tomato paste and bay leaf. Stir until well combined and the hardened coconut milk melts.
Add your beef back and toss all together. Serve.