Blitz the curry paste ingredients in a food processor until fine. Scrape down sides and blend completely.
Add the oil to a Dutch oven over medium high heat. Season the beef with salt and brown in batches. Don't over crowd the pot or it will steam. Set aside in bowl.
Over medium heat add the Curry Paste to the pan and cook 3 minutes, stirring often as it darkens and reduces.
Add the remaining ingredients (coconut milk through lemongrass stick) and the browned beef with accumulated juices. Stir together and bring to a simmer. Cover and cook on Low for 2 hours.
Remove lid and stir. Turn heat to medium and cook another 20-30 minutes until sauce reduces and thickens, stirring often.
Serve over steamed rice.
Notes
If using dried like chile de arbol found in most markets, rehydrate with boiling water in a small bowl. Otherwise use fresh red Thai chiles (cayenne). Feel free to cut chiles in half, this is spicy!
Trim the root end and peel the reedy green outer shell to reveal the softer white part on the bottom half of the lemongrass. Chop into 1-inch pieces.
Galangal is like ginger but it has a peppery flavor. If you can't find it, substitute with more ginger and a grind of black pepper. Use a small spoon to scrape the outer skin off, then chop.
Use a small spoon to scrape the outer skin off, then chop.
If using tamarind pulp, soak in 1 tbsp of hot water, then remove seeds. Equal amount of white vinegar can be substituted if you can't find. It can be purchased in most Asian markets (I but the Tamicon brand).
Kaffir lime leaves are worth hunting down in most Asian/South East Asian markets and have the most amazing, concentrated lime aroma. I stack them, then roll up like a cigar and slice fine for long, thin strips. You can substitute with dried kaffir lime leaves and crush them. Lastly, you can substitute by using 1 tablespoon fresh lime juice and the zested rind of 1 lime.