Mix together the flour, five-spice powder and some salt and pepper in a bowl. Toss the beef in the flour mixture and set aside.
Heat the butter and olive oil in a heavy-bottomed pot over medium-high heat. Working in 2 batches, sear the meat on all sides until golden brown, 3 to 4 minutes per batch. Remove the meat to a plate and set aside.
To the pot, add the ginger, chili paste, garlic and scallion whites. Cook, stirring constantly, for 2 minutes. Deglaze with the sherry, scraping up any bits from the bottom of the pot. Add the broth, soy sauce, honey, star anise and bay leaves and bring the mixture to a boil. Add the seared beef, cover the pot, transfer to the oven and cook until the meat is falling apart, about 2 hours.
Serve over rice, garnished with the reserved scallion greens.