Grind all the ingredients for the spice paste together.
Heat up a stock pot and cooking oil. Add the spice paste and stir over medium heat until it is fragrant. This takes 10 minutes, so be patient or the mee siam will not be delicious.
Scoop up 1/3 of the paste and put that into another pot.
Onto the 2/3 of the paste, add 1 litre of stock, assam juice, sugar and salt. Bring to a boil.
Add prawns to the pot and when cooked, remove the prawns to be used for toppings.
Add the noodles to the 1/3 of the paste that was reserved, stir through and mix until even.
Put noodles into five bowls, arrange toppings on the noodles, and scoop the gravy over the noodles.
Serve with a wedge of lime and/or more sambal chili.