In a saucepan, gently warm the cream (do not boil), add lemongrass (chopped in long sticks), turn off the heat and let steep.
Heat up the olive in a high bottom frying pan (medium heat) and add the tomato, salt and pepper, fry a little to remove moisture. Toss in roughly chopped garlic, ginger and jalapeno. Cook down well until a thick paste-like consistency. Taste - it should be on the over-seasoned side.
Turn up the heat a little and add the prawns in. Toss with the tomato sauce until well coated and the prawns are just cooked.
Add the cream and lemongrass infusion. Garnish with coriander. Turn off the heat and cover the pan until served.
Serve with chopped up Portuguese bread ;)