Heat a deep saute pan over a medium heat, and add the vegetable oil.
Saute the lemongrass stalks and kaffir lime leaves until aromatic. This takes around 2 minutes.
Turn the heat up to medium-high and add the arborio rice. Toast the rice in the aromatic oil until slightly golden brown.
| Unlike Asian rice dishes, the liquid is added gradually in risotto, while the rice is stirred. This is to encourage the natural starch in the rice to come out and thicken the sauce, making it a luscious dish. So don’t rinse your rice when you’re making risotto!
Add the fish stock in 6 portions, stirring until the stock has been almost totally absorbed by the rice each time.
On the last addition of fish stock, stir in the oyster mushrooms and cherry tomatoes as well.
| To make this into a chicken tom yum risotto, use some sliced chicken breast instead of prawns, and replace the fish stock with chicken stock - To turn this into a vegan risotto, replace the tom yum paste with some tomato paste, and replace the fish stock with vegetable stock. Don’t forget to season with salt, sugar and lime juice!
Top the risotto with the prawns, and cover the pan to steam the prawns for 5-7 minutes.
When you open the pan, the prawns should be perfectly cooked and most of the stock should be absorbed.
| If you don’t want to use prawns, you can replace it with another type of seafood, such as sliced fish, mussels or clams.
Stir in some fresh coriander, and top with a squeeze of fresh lime before serving! | If you want to add a good kick of spice, add some chopped birds’ eye chilli in with the tom yum paste.