A mortor and pestle are the most authentic tools for making curry paste, but feel free to use a clean coffee or spice grinder and a food processor they're a lot quiker and easier.
Place the coriander seeds and cumin seeds in a small skillet over medium heat, and toast until fragrant (1 to 2 minutes). Let cool. Place spices in a spice or coffee grinder with peppercorns, and process until finely ground. Combine the spice mixture, shallots, and remaining ingredients in a food processor. Process until smooth. Refrigerate the remaining curry paste in an airtight container for up to 2 weeks.