Blend or finely mince the shallots and garlic with the ground coriander and cumin to make a rough paste.
Add the beef, spice paste, galangal, bay leaves, lemongrass, kecap manis, palm sugar, salt and water to a pot. The beef should be just covered. Bring to a boil, then reduce to a gentle simmer.
Cover and simmer for 70 to 80 minutes, until a knife slides into the beef with little resistance. Add a splash of water if the liquid drops below the meat.
Lift the beef out and set the pot of liquid aside. Let the beef cool for 10 minutes, then place a piece inside a zip bag or between plastic wrap and pound with a rolling pin to about 1 cm thick. Repeat with the other pieces.
Boil the leftover liquid hard for 8 to 10 minutes until reduced to about 1/2 cup of thick glaze. Strain.
Heat the oil in a large nonstick or cast iron skillet over medium-high heat. Fry the pounded beef for 3 to 4 minutes per side, without moving it, until deeply browned with crisp edges.
Brush or spoon the reduced glaze over the beef in the last minute of frying. Serve with rice, cucumber and sambal.