Prepare the spice paste: combine chili powder, ground coriander, ground cumin, 1 tsp salt, chopped galangal, lemongrass (white part), cilantro stems/roots, shallots, garlic, roasted peanuts, shrimp paste, and 1 tablespoon water in a blender or mortar and pestle and process to a smooth paste.
Heat 1 tablespoon oil in a wok or large skillet over medium heat. Add shredded kaffir lime leaves and stir-fry 30 seconds until fragrant.
Add the spice paste to the wok and stir-fry 1–2 minutes until fragrant, then continue stirring over medium heat until the oil begins to separate slightly from the paste.
Turn heat to medium-high, add the sliced beef and stir-fry about 2 minutes until the exterior is seared.
Pour in the coconut cream and briefly bring to a light boil for 1–2 minutes, stirring to combine.
Add 1 tablespoon palm sugar and 1 tablespoon fish sauce, stir well, then reduce heat to medium-low, cover, and simmer gently for 45–60 minutes until the beef is tender.
Adjust seasoning with additional salt, fish sauce, or a bit of sugar to taste; if the curry is too dry, stir in a little water to reach your desired consistency.
Serve hot with steamed jasmine rice.
