Definitely use red Thai curry paste instead of curry powder. Float a few kaffir lime leaves if you have them, too. We LOVED this. I also made Thai rice noodles for my husband and ladled the mussels and broth over them. Served with a very simple salad of baby greens, sliced mango, and kiwi with a drizzle of orange juice, olive oil (just a tiny bit), and a squirt of lime.
This dish was great! It makes a big difference if you have quality mussels. I sub red curry paste and it was a bit hot,so be careful. I suggest tasting the sauce too check heat and flavors. I also added green onions to the garnish. My hubby suggested we pour the sauce back over the mussels and that turned out very good. Cooked in 3 minutes. Served with baguette and salad and ate every bite!