01 - Combine beef cubes, water, bay leaves, kaffir lime leaves, lemongrass, and salt in a large pot. Bring to a boil over high heat, then reduce heat and simmer covered for 45 to 60 minutes until beef is tender. Remove beef from broth and reserve the stock for sauce preparation.
02 - Combine shallots, garlic, chilies, candlenuts, coriander, cumin, turmeric, ginger, galangal, and white pepper in a blender. Process until a smooth paste forms, adding minimal water only if necessary to facilitate blending.
03 - Thread cooked beef cubes onto pre-soaked bamboo skewers. Grill over hot charcoal or preheated grill pan for 4 to 6 minutes, turning frequently and basting lightly with oil, until exterior develops slight char and smoky flavor.
04 - Heat vegetable oil in a saucepan over medium heat. Add spice paste and sauté for 3 to 4 minutes, stirring constantly, until fragrant and oil begins to separate. Pour in 1.7 cups reserved beef stock, then add salt and sugar. Bring mixture to a gentle simmer.
05 - Whisk rice flour with 2 tablespoons water in a small bowl until smooth. Gradually pour slurry into simmering sauce while stirring continuously. Continue cooking for 3 to 4 minutes until sauce thickens and achieves glossy, smooth consistency.
06 - Arrange grilled beef skewers on serving plates. Pour hot thickened sauce generously over skewers, ensuring each piece is well-coated. Sprinkle fried shallots over top and serve with sliced rice cake on the side if desired.