Make the chilli mix: Place large saucepan on high heat and add the oil and lemongrass. Add the chilli, ginger, garlic, eschallots and coriander root to the the saucepan, stirring constantly. The ingredients should start to caramelise quite quickly. Add the palm sugar and continue cooking until the chillies become soft. Then add the fish sauce and cherry tomatoes, breaking the tomatoes down using the back of your wooden spoon. Keep stirring the mix until all the ingredients are soft and then blend the entire mix into a rough paste. Set aside.

Place a large frying pan on high heat and add the olive oil, chilli paste and crabs. Fry the crabs off in the pan for a minute, making sure to stir them constantly. Add the coconut milk and put the lid on for a minute or so to help steam the crabs. Cook for five minutes, then serve. Generously the divide the crab and sauce into four bowls and throw a handful of sambal over the top and serve with coconut rice. 

Tip: Be sure not to overcook the crabs or they will start to break down and turn to mush. Don't wear anything white when you're making this as you're bound to get messy; provide fingerbowls for your guests.