1. Cook pork until cooked through (2-3 minutes), season to taste, remove, drain on absorbent paper, set aside to cool. Repeat with chicken and prawns, cooking separately.
2. Pound coriander and garlic paste and peppercorns in a mortar to a fine paste. Heat oil in a frying pan over high heat, add paste and fry until fragrant (1-2 minutes).
3. Add palm sugar and fish sauce to coriander and garlic paste, simmer until slightly thickened (4-5 minutes). Add pork, chicken and prawns and stir until reduced (3-4 minutes). Stir through half of each of the fried shallots, fried garlic and peanuts and set aside to cool slightly
4. Top pineapple slices with pork mixture, scatter with julienned chilli, lime leaf and coriander and serve with remaining fried shallots, fried garlic and peanuts.