We had a sneaky look at the Wagamama's website to try and work out what we could put together to get a similar result. I have to admit, ours didn't turn out quite the same, but it definitely captured the 'essence' of the dish and was a pretty good home made attempt!
chopped chicken breast
lemongrass (we used a teaspoon of the powdered type, but the real stuff would be better)
can of coconut milk
one chili (we also threw in some chili flakes)
a red onion
stir fry veg- we used bean sprouts, pepper, bamboo shoots and cabbage
a couple of cups of water
a squeeze of lemon or lime
a twist of salt and pepper
Then simply add your can of coconut milk, noodles (we used fresh ones, but if you use the dried type, cook them first!) and a couple of cups of water to your stir fry and let this simmer. Pour in your lemon juice and sprinkle in the salt and pepper. Joss and I also added a few more pinches of lemon grass here as well.
Leave on the heat for 10 or 15mins just to let the flavours infuse through and there we are, one delicious (almost) restaurant quality dish, made by you!
P.S. I think this would be amazing if you added a teaspoon of thai green curry paste to your veg- if you do, tell us how it tastes!