Soak red chillies in boiling water for 15 minutes. Drain and chop. Heat a frying pan, add the peppercorns, coriander, cumin and turmeric and dry fry over medium heat for 3 minutes. Transfer to mortar and pestle or food processor and grind to fine powder. Place ground spices, chilli, ginger, garlic, shallots, lemon grass and shrimp paste in mortar and pestle or processor and grind until smooth. Stir in the lime rind.
Add 3 tblspn curry paste to milk and vegetable stock. Add all ingredients except fish sauce and palm sugar to slow cooker. Cook on high for 2 hours and low for 1 hour. Stir in fish sauce and palm sugar. Serve over rice noodles or rice.